Component carrier activation/deactivation in multi carrier systems

ABSTRACT

Methods and apparatus for addressing wireless transmit/receive unit (WTRU) behavior in response to configuration, configuration parameters and access issues related to the activation/deactivation process when the WTRU may be configured with multiple serving cells or carrier aggregation.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/522,801 filed Oct. 24, 2014, which is a continuation of U.S. patentapplication Ser. No. 12/950,622 filed Nov. 19, 2010, now U.S. Pat. No.8,917,605 issued Dec. 23, 2014, which claims the benefit of U.S.Provisional Patent Applications Nos. 61/262,810 filed Nov. 19, 2009;61/293,520 filed Jan. 8, 2010; 61/304,149 filed Feb. 12, 2010;61/307,803 filed Feb. 24, 2010; 61/314,446 filed Mar. 16, 2010;61/330,150 filed Apr. 30, 2010; 61/355,756 filed Jun. 17, 2010; and61/373,678 filed Aug. 13, 2010, all of which are incorporated herein byreference in their entireties.

FIELD OF THE INVENTION

This application is related to wireless communications.

BACKGROUND

In Long Term Evolution (LTE) Release 8 (R8), a base station mayconfigure a wireless transmit/receive unit (WTRU) with downlink (DL) anduplink (UL) resources on a single DL carrier and a single UL carrier,respectively. The pair of DL and UL carriers may be considered to form acell of the wireless network. The WTRU may take certain actions inresponse to the configuration, configuration parameters and accessissues related to the activation/deactivation process. In LTE R8, thereis no ambiguity from the perspective of the WTRU in taking action sincethe DL and UL resources are associated with the single DL carrier andthe single UL carrier, respectively, which form a serving cell of theWTRU. In multi-carrier wireless systems, the WTRU may be assignedmultiple serving cells, each consisting of one DL component carrier andpossibly also one UL component carrier (CC). The WTRU may need to actand respond differently if the WTRU may be configured with multipleserving cells.

SUMMARY

Methods and apparatus for addressing wireless transmit/receive unit(WTRU) behavior in response to configuration, configuration parametersand access issues related to the activation/deactivation process whenthe WTRU may be configured with multiple serving cells or carrieraggregation.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,given by way of example in conjunction with the accompanying drawingswherein:

FIG. 1A is a system diagram of an example communications system in whichone or more disclosed embodiments may be implemented;

FIG. 1B is a system diagram of an example wireless transmit/receive unit(WTRU) that may be used within the communications system illustrated inFIG. 1A; and

FIG. 1C is a system diagram of an example radio access network and anexample core network that may be used within the communications systemillustrated in FIG. 1A.

DETAILED DESCRIPTION

FIG. 1A is a diagram of an example communications system 100 in whichone or more disclosed embodiments may be implemented. The communicationssystem 100 may be a multiple access system that provides content, suchas voice, data, video, messaging, broadcast, etc., to multiple wirelessusers. The communications system 100 may enable multiple wireless usersto access such content through the sharing of system resources,including wireless bandwidth. For example, the communications systems100 may employ one or more channel access methods, such as code divisionmultiple access (CDMA), time division multiple access (TDMA), frequencydivision multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrierFDMA (SC-FDMA), and the like.

As shown in FIG. 1A, the communications system 100 may include wirelesstransmit/receive units (WTRUs) 102 a, 102 b, 102 c, 102 d, a radioaccess network (RAN) 104, a core network 106, a public switchedtelephone network (PSTN) 108, the Internet 110, and other networks 112,though it will be appreciated that the disclosed embodiments contemplateany number of WTRUs, base stations, networks, and/or network elements.Each of the WTRUs 102 a, 102 b, 102 c, 102 d may be any type of deviceconfigured to operate and/or communicate in a wireless environment. Byway of example, the WTRUs 102 a, 102 b, 102 c, 102 d may be configuredto transmit and/or receive wireless signals and may include userequipment (UE), a mobile station, a fixed or mobile subscriber unit, apager, a cellular telephone, a personal digital assistant (PDA), asmartphone, a laptop, a netbook, a personal computer, a touchpad, awireless sensor, consumer electronics, and the like.

The communications systems 100 may also include a base station 114 a anda base station 114 b. Each of the base stations 114 a, 114 b, may be anytype of device configured to wirelessly interface with at least one ofthe WTRUs 102 a, 102 b, 102 c, 102 d to facilitate access to one or morecommunication networks, such as the core network 106, the Internet 110,and/or the networks 112. By way of example, the base stations 114 a, 114b may be a base transceiver station (BTS), a Node-B, an eNode B, a HomeNode B, a Home eNode B, a site controller, an access point (AP), awireless router, and the like. While the base stations 114 a, 114 b areeach depicted as a single element, it will be appreciated that the basestations 114 a, 114 b may include any number of interconnected basestations and/or network elements.

The base station 114 a may be part of the RAN 104, which may alsoinclude other base stations and/or network elements (not shown), such asa base station controller (BSC), a radio network controller (RNC), relaynodes, etc. The base station 114 a and/or the base station 114 b may beconfigured to transmit and/or receive wireless signals within aparticular region, which may be referred to as a cell (not shown). Thecell may further be divided into cell sectors. For example, the cellassociated with the base station 114 a may be divided into threesectors. Thus, in one embodiment, the base station 114 a may includethree transceivers, i.e., one for each sector of the cell. In anotherembodiment, the base station 114 a may employ multiple-input multipleoutput (MIMO) technology and, therefore, may utilize multipletransceivers for each sector of the cell.

The base stations 114 a, 114 b may communicate with one or more of theWTRUs 102 a, 102 b, 102 c, 102 d over air interface(s) 116, which may beany suitable wireless communication link (e.g., radio frequency (RF),microwave, infrared (IR), ultraviolet (UV), visible light, etc.). Theair interface 116 may be established using any suitable radio accesstechnology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 114 a in the RAN 104 and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access (UTRA), whichmay establish the air interface 116 using wideband CDMA (WCDMA). WCDMAmay include communication protocols such as High-Speed Packet Access(HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed DownlinkPacket Access (HSDPA) and/or High-Speed Uplink Packet Access (HSUPA).

In another embodiment, the base station 114 a and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Evolved UMTSTerrestrial Radio Access (E-UTRA), which may establish the air interface116 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as IEEE 802.16 (i.e.,Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000,CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), InterimStandard 95 (IS-95), Interim Standard 856 (IS-856), Global System forMobile communications (GSM), Enhanced Data rates for GSM Evolution(EDGE), GSM EDGE (GERAN), and the like.

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement any combination of the aforementioned radiotechnologies. For example, the base station 114 a and the WTRUs 102 a,102 b, 102 c may each implement dual radio technologies such as UTRA andE-UTRA, which may concurrently establish one air interface using WCDMAand one air interface using LTE-A respectively.

The base station 114 b, in FIG. 1A may be a wireless router, Home NodeB, Home eNode B, or access point, for example, and may utilize anysuitable RAT for facilitating wireless connectivity in a localized area,such as a place of business, a home, a vehicle, a campus, and the like.In one embodiment, the base station 114 b and the WTRUs 102 c, 102 d mayimplement a radio technology such as IEEE 802.11 to establish a wirelesslocal area network (WLAN). In another embodiment, the base station 114 band the WTRUs 102 c, 102 d may implement a radio technology such as IEEE802.15 to establish a wireless personal area network (WPAN). In yetanother embodiment, the base station 114 b, and the WTRUs 102 c, 102 dmay utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,LTE-A, etc.) to establish a picocell or femtocell. As shown in FIG. 1A,the base station 114 b may have a direct connection to the Internet 110.Thus, the base station 114 b, may not be required to access the Internet110 via the core network 106.

The RAN 104 may be in communication with the core network 106, which maybe any type of network configured to provide voice, data, applications,and/or voice over internet protocol (VoIP) services to one or more ofthe WTRUs 102 a, 102 b, 102 c, 102 d. For example, the core network 106may provide call control, billing services, mobile location-basedservices, pre-paid calling, Internet connectivity, video distribution,etc., and/or perform high-level security functions, such as userauthentication. Although not shown in FIG. 1A, it will be appreciatedthat the RAN 104 and/or the core network 106 may be in direct orindirect communication with other RANs that employ the same RAT as theRAN 104 or a different RAT. For example, in addition to being connectedto the RAN 104, which may be utilizing an E-UTRA radio technology, thecore network 106 may also be in communication with another RAN (notshown) employing a GSM radio technology.

The core network 106 may also serve as a gateway for the WTRUs 102 a,102 b, 102 c, 102 d to access the PSTN 108, the Internet 110, and/orother networks 112. The PSTN 108 may include circuit-switched telephonenetworks that provide plain old telephone service (POTS). The Internet110 may include a global system of interconnected computer networks anddevices that use common communication protocols, such as thetransmission control protocol (TCP), user datagram protocol (UDP) andthe internet protocol (IP) in the TCP/IP internet protocol suite. Thenetworks 112 may include wired or wireless communications networks ownedand/or operated by other service providers. For example, the networks112 may include another core network connected to one or more RANs,which may employ the same RAT as the RAN 104 or a different RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities, i.e., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks. For example, the WTRU 102 c shown in FIG. 1A may be configured tocommunicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 1B is a system diagram of an example WTRU 102. As shown in FIG. 1B,the WTRU 102 may include a processor 118, a transceiver 120, atransmit/receive element 122, a speaker/microphone 124, a keypad 126, adisplay/touchpad 128, non-removable memory 130, removable memory 132, apower source 134, a global positioning system (GPS) chipset 136, andother peripherals 138. It will be appreciated that the WTRU 102 mayinclude any sub-combination of the foregoing elements while remainingconsistent with an embodiment.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Array (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and the like. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. While FIG. 1Bdepicts the processor 118 and the transceiver 120 as separatecomponents, it will be appreciated that the processor 118 and thetransceiver 120 may be integrated together in an electronic package orchip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, thetransmit/receive element 122 may be an antenna configured to transmitand/or receive RF signals. In another embodiment, the transmit/receiveelement 122 may be an emitter/detector configured to transmit and/orreceive IR, UV, or visible light signals, for example. In yet anotherembodiment, the transmit/receive element 122 may be configured totransmit and receive both RF and light signals. It will be appreciatedthat the transmit/receive element 122 may be configured to transmitand/or receive any combination of wireless signals.

In addition, although the transmit/receive element 122 is depicted inFIG. 1B as a single element, the WTRU 102 may include any number oftransmit/receive elements 122. More specifically, the WTRU 102 mayemploy MIMO technology. Thus, in one embodiment, the WTRU 102 mayinclude two or more transmit/receive elements 122, e.g., multipleantennas, for transmitting and receiving wireless signals over the airinterface 116.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as UTRA and IEEE 802.11, forexample.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128, (e.g., a liquid crystal display (LCD), displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 130 and/or the removable memory 132.The non-removable memory 130 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. For example, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to the GPS chipset 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 116 from abase station (e.g., base stations 114 a, 114 b,) and/or determine itslocation based on the timing of the signals being received from two ormore nearby base stations. It will be appreciated that the WTRU 102 mayacquire location information by way of any suitablelocation-determination method while remaining consistent with anembodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, and the like.

FIG. 1C is a system diagram of the RAN 104 and the core network 106according to an embodiment. As noted above, the RAN 104 may employ anE-UTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102c over the air interface 116. The RAN 104 may also be in communicationwith the core network 106.

The RAN 104 may include eNode-Bs 140 a, 140 b, 140 c, though it will beappreciated that the RAN 104 may include any number of eNode-Bs whileremaining consistent with an embodiment. The eNode-Bs 140 a, 140 b, 140c may each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In one embodiment,the eNode-Bs 140 a, 140 b, 140 c may implement MIMO technology. Thus,the eNode-B 140 a, for example, may use multiple antennas to transmitwireless signals to, and receive wireless signals from, the WTRU 102 a.

Each of the eNode-Bs 140 a, 140 b, 140 c may be associated with one ormore cells (not shown), each possibly on different carrier frequencies,and may be configured to handle radio resource management decisions,handover decisions, scheduling of users in the uplink and/or downlink,and the like. As shown in FIG. 1C, the eNode-Bs 140 a, 140 b, 140 c maycommunicate with one another over an X2 interface.

The core network 106 shown in FIG. 1C may include a mobility managementgateway (MME) 142, a serving gateway 144, and a packet data network(PDN) gateway 146. While each of the foregoing elements are depicted aspart of the core network 106, it will be appreciated that any one ofthese elements may be owned and/or operated by an entity other than thecore network operator.

The MME 142 may be connected to each of the eNode-Bs 142 a, 142 b, 142 cin the RAN 104 via an Si interface and may serve as a control node. Forexample, the MME 142 may be responsible for authenticating users of theWTRUs 102 a, 102 b, 102 c, bearer setup/configuration/release, selectinga particular serving gateway during an initial attach of the WTRUs 102a, 102 b, 102 c, and the like. The MME 142 may also provide a controlplane function for switching between the RAN 104 and other RANs (notshown) that employ other radio technologies, such as GSM or WCDMA.

The serving gateway 144 may be connected to each of the eNode Bs 140 a,140 b, 140 c in the RAN 104 via the Si interface. The serving gateway144 may generally route and forward user data packets to/from the WTRUs102 a, 102 b, 102 c. The serving gateway 144 may also perform otherfunctions, such as anchoring user planes during inter-eNode B handovers,triggering paging when downlink data is available for the WTRUs 102 a,102 b, 102 c, managing and storing contexts of the WTRUs 102 a, 102 b,102 c, and the like.

The serving gateway 144 may also be connected to the PDN gateway 146,which may provide the WTRUs 102 a, 102 b, 102 c with access topacket-switched networks, such as the Internet 110, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and IP-enableddevices.

The core network 106 may facilitate communications with other networks.For example, the core network 106 may provide the WTRUs 102 a, 102 b,102 c with access to circuit-switched networks, such as the PSTN 108, tofacilitate communications between the WTRUs 102 a, 102 b, 102 c andtraditional land-line communications devices. For example, the corenetwork 106 may include, or may communicate with, an IP gateway (e.g.,an IP multimedia subsystem (IMS) server) that serves as an interfacebetween the core network 106 and the PSTN 108. In addition, the corenetwork 106 may provide the WTRUs 102 a, 102 b, 102 c with access to thenetworks 112, which may include other wired or wireless networks thatare owned and/or operated by other service providers.

When referred to hereafter, the Physical Downlink Control CHannel(PDCCH) refers to the control channel used in LTE for scheduling ofradio resources, e.g. the control channel on which the WTRU receivesdownlink control information (DCIs) messages. DCIs are mainly used forscheduling downlink and uplink resources in the control region of adownlink frequency on which the WTRU operates. It also refers to thecase where the WTRU is a relay eNB for which the PDCCH channel is mappedon another downlink channel, (e.g. a PDSCH of the relay eNBconfiguration), to form the relay PDCCH (R-PDCCH).

When referred to hereafter, the term “Component Carrier (CC)” includes,without loss of generality, a frequency on which the WTRU operates. Forexample, a WTRU may receive transmissions on a downlink CC (hereafter“DL CC”). A DL CC may comprise a number of DL physical channelsincluding, but not limited to, the Physical Control Format IndicatorChannel (PCFICH), the Physical Hybrid Automatic Repeat Request IndicatorChannel (PHICH), the PDCCH, the physical multicast data channel (PMCH)and the physical downlink shared channel (PDSCH). On the PCFICH, theWTRU receives control data indicating the size of the control region ofthe DL CC. On the PHICH, the WTRU may receive control data indicatinghybrid automatic repeat request (HARQ) acknowledgement/negativeacknowledgement (ACK/NACK) feedback for a previous uplink transmission.On the PDCCH, the WTRU receives DCI messages that are mainly used forscheduling downlink and uplink resources. On the PDSCH, the WTRU mayreceive user and/or control data. For example, a WTRU may transmit on anuplink CC (hereafter “UL CC”). An UL CC may comprise of a number of ULphysical channels including, but not limited to, the physical uplinkcontrol channel (PUCCH) and the physical uplink shared channel (PUSCH).On the PUSCH, the WTRU may transmit user and/or control data. On thePUCCH, and in some cases on the PUSCH, the WTRU may transmit uplinkcontrol information, (such as channel quality indicator/precoding matrixindex/rank indication (CQI/PMI/RI) or scheduling request (SR)), and/orHARQ ACK/NACK feedback. On a UL CC, the WTRU may also be allocateddedicated resources for transmission of Sounding Reference Signals(SRS).

A cell typically minimally consists of a DL CC which is, optionally,linked to a UL CC based on the system information (SI) received by theWTRU either broadcasted on the DL CC or possibly using dedicatedconfiguration signaling from the network. For example, when broadcastedon the DL CC, the WTRU may receive the uplink frequency and bandwidth ofthe linked UL CC as part of the SystemInformationBlockType2 (SIB2)information element.

When referred to hereafter, the term “Primary Cell (PCell)” includes,without loss of generality, the cell operating in the primary frequencyin which the WTRU either performs the initial connection establishmentprocedure or initiates the connection re-establishment procedure, or thecell indicated as the primary cell in the handover procedure. The WTRUuses the PCell to derive the parameters for the security functions andfor upper layer system information such as NAS mobility information.Other functions that may be supported only on the PCell DL may includeSI acquisition and change monitoring procedures on the broadcast channel(BCCH), and paging. The UL CC of the PCell may correspond to the CCwhose PUCCH resources are configured to carry all HARQ ACK/NACK feedbackfor a given WTRU.

When referred to hereafter, the term “Secondary Cell (SCell)” includes,without loss of generality, the cell operating on a secondary frequencywhich may be configured once an RRC connection is established and whichmay be used to provide additional radio resources. System informationrelevant for operation in the concerned SCell is typically providedusing dedicated signaling when the SCell is added to the WTRU'sconfiguration. Although the parameters may have different values thanthose broadcasted on the downlink of the concerned SCell using thesystem information (SI) signaling, this information is herein referredto as SI of the concerned SCell independent of the method used by theWTRU to acquire this information.

When referred to hereafter, the terms “PCell DL” and “PCell UL”correspond to, without loss of generality, the DL CC and the UL CC ofthe PCell, respectively. Similarly, the terms “SCell DL” and “SCell UL”correspond to the DL CC and the UL CC, if configured, of a SCell,respectively. For the PCell, a CC may also be referred to as a PCC andfor a SCell, a CC may be referred to as a SCC.

When referred to hereafter, the term “serving cell” includes, withoutloss of generality, a primary cell (i.e. a PCell) or a secondary cell(i.e. a SCell). More specifically, for a WTRU that is not configuredwith any SCell or that does not support operation on multiple componentcarriers, (i.e. carrier aggregation), there may be only one serving cellcomprising of the Pcell. For a WTRU that is configured with at least oneSCell, the term “serving cells” includes the set of one or more cellscomprising of the PCell and all configured SCell(s).

When a WTRU is configured with at least one SCell, there is one PCellDL, (i.e., including one DL-SCH), and one PCell UL, (i.e., including oneUL-SCH), and, for each configured SCell, there is one SCell DL andoptionally one SCell UL, if configured.

The principles of activation and deactivation of a CC from the WTRUperspective herein may apply to at least one of a plurality of functionsrelated to the CC. For example, for a DL CC, it may relate to PDCCHmonitoring/decoding of a subset or all DCI formats such as UL DCIs, DLDCIs, both, or subsets thereof or PDSCH buffering/decoding. For a UL CC,it may relate for example to a PUSCH transmission, to a PUCCHtransmission, to the transmission of CQI/PMI/RI or SRS transmission.

The methods described herein are applicable upon SCellactivation/deactivation, without excluding an activation/deactivationwhich is a consequence of a reconfiguration that either adds or removesthe SCell.

The examples described herein are generally applicable independently ofwhether or not DRX is configured and/or applicable for the servingcell(s).

The methods described herein are equally applicable where any DL CC andany UL CC are activated and deactivated independently, including DL andUL CCs associated to each other and including CCs that belong either toa PCell or to a SCell, and also to multiple CCs sharing the sameactivation/deactivation state.

A WTRU configured with at least one SCell may be configured withcross-carrier scheduling for one or more serving cells. Cross-carrierscheduling is a control signaling method where physical radio resources(DL transmission) for PDSCH transmissions on the DL CC, or grantedresources (UL transmission) for PUSCH transmissions on the UL CC, of afirst serving cell may be assigned using the PDCCH of the DL CC of asecond serving cell.

The term CC may refer to one or more DL CC(s), one or more UL CCs and/ora combination thereof and in particular the combination of a DL CC and aUL CC forming a serving cell of the WTRU's configuration, (i.e., eithera PCell or a SCell). Such a combination of CCs may be achieved byconfiguration of the WTRU using associations between one or more ULCC(s) and one or more DL CC(s), for the purpose of assigning DLtransmission resources, granting UL transmission resources, transmissionof CQI/PMI/RI feedback, HARQ feedback, or for the transmissions relatedto the Random Access (RA) procedure, and the like.

The association between multiple configured CCs for a given WTRU may bebased on, for example, at least one of the following methods: a set ofconfigured CCs may be based on UL/DL associations such as “SIB2-linking”(e.g., by spectrum pairing, forming a cell of the system based either onbroadcasted SI (SIB2) and/or on SI signaled to the WTRU using dedicatedsignaling, and/or pairing for UL/DL PCC), “Scheduling-linking” e.g.based on the CC being addressable for scheduling from the PDCCH ofanother CC, “HARQ Feedback-linking” e.g. based on the HARQ feedbackrelationship (DL CC, UL PUCCH, and UL CC, DL Physical Hybrid AutomaticRepeat Request Indicator Channel (PHICH)), “Dedicated-linking” e.g.based on an RRC configuration for the cell (e.g., information elementsin the configuration message that include at least the uplink frequencyand bandwidth of the associated UL CC), and/or the use of other types ofsignaling (e.g., PHICH, PUCCH, PCFICH) between the base station and theWTRU across different CCs. A set of configured CCs may also be based onUL/UL associations derived from similar UL TA requirements and/orfrequency bands e.g. “Band-linking”. The configured CCs may also bebased on DL/DL associations such as those derived from cross-carrierscheduling on PDCCH from one DL CC for the PDSCH of a different DL CCwhich is a further refinement of “Scheduling-linking” described above.

As a consequence, activation and/or deactivation of a given CC may beexplicit using control signaling, or implicit based on some associationwith another CC, for example, by “SIB2-linking”, “Scheduling-linking”,“HARQ Feedback-linking”, “Dedicated-linking”, “Band-linking” orcombinations thereof. The use of the term “concerned SCell” herein maycover both explicit or implicit cases and may correspond to any methodused to provide the associations between a plurality of CCs to the WTRU.

The concerned SCell may be any SCell from the set of configured SCell(s)for the WTRU, including a SCell that may represent any of the following:a SCell that consists of a SCell DL associated with a SCell UL, a SCellDL configured without uplink resources, e.g., without associated SCellUL, any SCell DL independent of a possible associated SCell UL, or aSCell UL independent of a possible associated SCell DL. The concernedSCell may, or may not, transmit and/or receive control signalinginformation of its own e.g., by means of the PDCCH and/or PDSCH on aSCell DL.

In the example methods, activation and deactivation may be applied percell, i.e., the activation state of the UL CC follows the state of theassociated DL CC. This may be used with reference to the methodsdescribed herein without limiting its applicability to individuals CCs,to the PCell, or to other methods for associating a plurality of CCs.When referred to hereafter, the terms “SCell activation” and “SCelldeactivation” thus includes, without loss of generality, all the abovecases. For example, the concerned SCell may be the SCell which isactivated and/or deactivated implicitly e.g., by timer expiration orexplicitly by control signaling, such that both the SCell DL and theSCell UL that form the SCell as indicated by the System Informationprovided to the WTRU by either dedicated and/or broadcasted signaling,(e.g. using a SIB2 or SIB2-like information element), share the sameactivation/deactivation state.

A WTRU may be configured with at least one DL CC on which signaling forSCell activation (alternatively deactivation) may be received using: L1signaling (e.g., physical downlink control channel (PDCCH) formatcarrying a component carrier indicator field (CCIF) which corresponds tothe CC to which the activation/deactivation command applies; L2signaling (e.g., medium access control (MAC) control element (MAC CE);or L3 signaling (e.g., radio resource control (RRC) information element(RRC IE)). Each of the signaling methods may be used by the WTRU todetermine to which CC(s) (e.g. SCell) the received signaling applies. Asan example this signaling may be received on a transmission on the PCellDL, or alternatively also on a transmission for an activated SCell DL.

Described herein are example control signals that may be sent/receivedupon activation or deactivation and may be used standalone or incombination.

The WTRU may receive and decode control signaling to activate ordeactivate at least one concerned SCell, where the control signaling maybe received by the WTRU on the DL CC of any of the serving cells of theWTRU. The control signaling may, for example, be scrambled by C-RNTI, orby a new A-RNTI_i as defined herein.

In particular, the control signaling may be received by the WTRU usingat least one of L1, L2 and L3 signaling methods. For example, L3signaling (e.g., RRC) may use an information element (IE) in a RRCConnection Reconfiguration message, or a different IE. Alternatively, L2signaling (e.g., MAC) may use a control element (CE). Alternatively, L1signaling may use an existing DCI format with fixed codepoints and/orscrambled using a special RNTI indicating control signaling for thepurpose of SCell activation/deactivation (e.g., a carrieraggregation-radio network temporary identifier (CA-RNTI)). L1 may alsouse an explicit indication, e.g., a downlink control information (DCI)format with a component carrier identification field (CCIF) set to avalue corresponding to the concerned SCell, which CCIF value mayrepresent at least one of: the identity of the concerned SCell, a subsetof SCells, (e.g. an index to an item in a configured set of SCells), ora reserved codepoint indicating a plurality of SCells (e.g., allconfigured SCells for the WTRU). The DCI format may be an extension ofeither one or a combination of the following formats: a PDCCH order forrandom access (RA) with CCIF corresponding to the concerned SCell; aPDCCH DL assignment with CCIF corresponding to the concerned SCell; aPDCCH UL grant with CCIF corresponding to the concerned SCell; a PDCCHactivation with CCIF corresponding to the concerned SCell; or any of theL1 (e.g. PDCCH) , L2 or L3 message above, with an explicit fieldindicating whether or not the WTRU may perform RA.

Additional information may be included in the control signaling foractivation/deactivation. For example, the information may be anindication that at least one function may be restricted to a subset ofCCs, including the case where the function applies to a single CC. Thismay be indication that the WTRU may consider the CC(s) as PCC.Alternatively, it may be an indication that the mapping between UL/DLPCC may differ from the mapping between UL/DL as indicated by the systeminformation of the DL CC. As such, it may apply either to the UL PCC orthe DL PCC.

Described herein are scenarios and methods related to how the WTRUdetermines the identity and activation/deactivation state of a given CCaffected by activation and deactivation of SCells.

In one scenario, SCell identification for multiple SCells uponactivation/deactivation may be affected. The base station may configurethe WTRU with multiple SCells in addition to the PCell. If some or allof those SCells are not immediately activated by the configurationprocedure, a separate activation/deactivation mechanism may be used andmay support addressing individual SCells, which may require anothermechanism to identify the SCells. For example, the configured SCell(s)may be initially deactivated when added by a radio resource controller(RRC) reconfiguration procedure, (with or without the mobility controlinformation element), after a handover, (e.g. following the reception ofa RRC reconfiguration with the mobility control element), until firstactivated by reception of activation/deactivation control signaling,which control signaling includes an explicit identity of the SCell(s)for which the control signaling applies, e.g., by the reception of anactivation/deactivation MAC control element (CE) activating one or moreof the deactivated SCell(s).

In another scenario, the base station may configure the WTRU with anumber of DL CCs different than the number of UL CCs. For example, theremay be more DL CCs than UL CCs. How to convey this information to theWTRU may need to be addressed, in particular if SCell DL and SCell ULmay be activated and deactivated independently of any possibleassociation, and to avoid unnecessary or disallowed access to ULresources corresponding to a SCell for which the UL may not beconfigured.

For the purpose of activating a concerned SCell DL, the WTRU mayactivate the concerned SCell DL from the reception on a DL CC of any oneof: control signaling for transmissions on the concerned SCell DL (e.g.,DCI format 1/1A/1B/1C/1D/2/2A); any control signaling for the concernedSCell DL such as for example including a component carrier indicatorfield (CCIF) of the concerned SCell DL; or control signaling using anyone of a set of pre-determined signaling formats containing an identityof the concerned SCell DL such as a DCI format typically used forsignaling of UL resources containing a CCIF of the concerned SCell DL.For example, DCI format 0, (typically used for granting UL resources),DCI format 1A (typically used for DL assignment or PDCCH order forRACH), DCI format 3/3A (typically used for uplink power control); or anexisting format with a fixed codepoint may be used including anyextensions thereof. Another example may use an activation/deactivationMAC CE containing a bitmap, where each bit in the bitmap corresponds toa specific SCell and indicates whether the SCell may be in the activatedstate or in the deactivated state. A concerned SCell UL may be similarlyhandled using the corresponding signaling and formats.

The WTRU may deactivate a concerned SCell DL from reception of signalingsimilar to that described herein for the activation of a SCell DL.

For the purpose of activating a concerned SCell UL, the WTRU mayactivate the SCell UL from the reception of control signaling indicatingthat UL resources are granted, (e.g., a grant), to the WTRU (e.g., DCIformat 0 or DCI format 3/3A, for example augmented with a CCIFcorresponding either to the identifier of the SCell UL or to any SCellDL which may be associated with the SCell UL) and/or indicating that theWTRU may perform a procedure related to UL transmission, (e.g., a powercontrol message or request for random access). Alternatively, the WTRUmay activate the SCell UL from the reception of control signaling fortransmissions on a SCell DL, (e.g., DCI format 1/1A/1B/1C/1D/2/2A),associated with the SCell UL. The WTRU may also activate the SCell ULfrom the reception of any control signaling, (for example including CCIFfor the SCell DL), for a SCell DL associated with the SCell UL.

For example, a N-bit CCIF, (e.g., CCIF may be represented by a 3-bitvalue as an indication for 5 or more CCs), may represent a singlenumbering space for the identities of the DL CCs. Alternatively, it mayrepresent a single numbering space for the configured UL CCs.Alternatively, it may represent a single numbering space for theconfigured serving cells. Additional codepoints may be used to identifyall or a subset of the serving cells at one time. For example, it may beused to identify the SCells. The control signaling, (e.g., the UL grant,the DL assignment, the order to perform RA, or the power controlcommand), of the message may still be applied either to the serving cellwhere the signaling was received, to the UL CC associated with the DL CCwhere the signaling was received, (whether it is the UL CC or the DL CCmay depend on the nature of the signaling e.g., whether the controlsignaling is for an downlink or an uplink transmission), or to aspecific serving cell, (e.g., a PCell), of the WTRU configuration.

The WTRU may deactivate a concerned SCell UL from reception of signalingsimilar as described herein for the activation of a SCell UL.

For a SCell, for the purpose of activating a concerned SCell, the WTRUmay activate the concerned SCell DL and the concerned SCell UL, ifuplink resources are configured for the concerned SCell, from receptionof signaling similar as described above.

For a SCell, for the purpose of deactivating a concerned SCell, the WTRUmay deactivate the concerned SCell DL and the concerned SCell UL, ifuplink resources are configured for the concerned SCell, from receptionof signaling similar as described herein for the activation of a SCell.

Whether or not the WTRU may activate and/or deactivate a SCell UL fromthe implicit activation of an associated SCell DL may depend on any oneof the following factors. Rephrased, it may depend on whether or not theWTRU has received a configuration for uplink resources associated withthe SCell DL. In particular, it may depend on whether or not thededicated configuration includes configuration parameters for ULresources. It may also depend from the absence, (also indicatingimplicit release of the parameters if configured), for the correspondingUL/DL pair (cell) of some or all of the information elements (Ies). Forexample, in the PhysicalConfigDedicated IE, the PUCCH configuration(pucch-ConfigDedicated); PUSCH configuration (pusch-C onfigDedicated);power control configuration (uplinkPowerControlDedicated,tpc-PDCCH-ConfigPUCCH, tpc-PDCCH-ConfigPUSCH), CQI measurementconfiguration (cqi-ReportConfig), or sounding configuration(soundingRS-UL-ConfigDedicated) may be absent. There may also be anexplicit indication in the RRC configuration that a specific SCell ULmay not be used.

In the case where DCI format 1A may be used for the purpose ofactivating a SCell, the WTRU may determine that the signaling used forthe purpose of activating the SCell, (and not for the purpose of a PDCCHorder for random access channel (RACH) or for compact scheduling ofPDSCH), by checking the value(s) of certain fields. For example, the DCIformat 1A may be interpreted as an activation order if the fields areset in the same way as for a PDCCH order for RACH except that one orseveral bits in one of the fields that are set to pre-determined valuesin the case of a PDCCH order for RACH is (are) set to a differentvalue(s). Alternatively, the WTRU may determine that the signaling maybe used for the purpose of activation (or not) based on the value of theCCIF. For instance, the signaling may be interpreted as a PDCCH order inthe case where the CCIF is set to a specific value (e.g., 000), and asan activation command in the case where the CCIF is set to any othervalue which then represents one or more carriers to be activated.

In one example method, the control signaling described herein mayprovide sequential activation/deactivation. More specifically, the WTRUmay maintain a list of one or more configured SCell(s) following aspecific order, for example, based on configuration (e.g., RRC). Uponreception of a SCell activation command, the WTRU may activate the nextconfigured, but inactive SCell in the list. Similarly, upon reception ofa deactivation command, the WTRU may deactivate the active SCell thatwas activated the latest. Alternatively, the identity of the SCell beingactivated/deactivated may be obtained implicitly from the identity ofthe SCell from which the activation/deactivation command is received.Sequential activation/deactivation may occur within a configured set ofSCells (e.g., activation/deactivation of SCell set 1 may take priorityover set 2, etc.).

In another example method, a Radio Network Temporary Identifier may beallocated to identify control signaling sent on the PDCCH. This may beused by the WTRU to determine whether or not it shall act on receivedcontrol signaling and for which signaling it attempts decoding. Whenreferred hereafter, the A-RNTI_i is used to denote an RNTI reserved foractivation/deactivation functionality. The A-RNTI_i described herein mayhave WTRU-dedicated RNTI values, for example one for each CC, SCell,and/or for the activation/deactivation command, or identical RNTIvalues, for example a single RNTI to identify theactivation/deactivation command and/or for indicating that the commandis applicable to all configured SCells. The WTRU may receive and decode,in any serving cell, control signaling (scrambled by C-RNTI, or byA-RNTI_i) to activate at least one concerned SCell.

Described herein are scenarios and methods related to implicit andexplicit activation and deactivation of a given CC affected byactivation and deactivation of SCells.

If a DL CC is activated for which the corresponding PDCCH may beactivated, and in case cross-carrier scheduling is possible from thatPDCCH, it may be desirable to have methods to ensure that any otherrelevant SCells may be scheduled as soon as possible. This assumes thatthe cross-carrier scheduling relationship between different configuredserving cells is known, (e.g., configured), at the time the activationcommand is received. Otherwise, if this relationship is not known, itmay be useful to provide means for a WTRU to determine which DL CC maybe used to schedule newly activated SCell(s) based on the activationcontrol signaling. For example, the WTRU may receive in a RRC messagethat configures the dedicated physical radio resource configuration fora SCell, e.g., a PhysicalConfigDedicatedSCell IE, a configuration forthe cross-carrier scheduling of the SCell, e.g., aCrossCarrierSchedulingConfig IE, which configuration includes anidentity of the serving cell used to schedule the SCell in casecross-carrier scheduling is applicable to the SCell.

When the WTRU activates a concerned SCell, the WTRU may activate theSCell DL from the reception of the control signaling. If the WTRU isconfigured to monitor the PDCCH of the DL of the concerned SCell, theWTRU may additionally activate any other SCell for which said PDCCH mayalso provide control signaling, (e.g., DL assignments, UL grants, othercontrol messages, e.g., power control commands). That is, the WTRU mayactivate any other SCell for which cross-carrier scheduling from thePDCCH of the DL of the concerned SCell may be applicable. Restated, if aSCell is not active which SCell is configured with cross-carrierscheduling for, or alternatively from, the concerned SCell, then theWTRU may additionally activate that SCell together with the concernedSCell.

When the WTRU deactivates a concerned SCell, the WTRU may deactivate asecond SCell following the deactivation of the concerned SCell DL if theconcerned SCell DL was previously used to provide control signaling(e.g., DL assignments, UL grants, other control messages, e.g., powercontrol commands) and/or if no control signaling is further possible forthe second SCell following the deactivation of the concerned SCell. Forexample, if the concerned SCell is deactivated which may have beenneeded for control signaling purposes for the second CC, then the WTRUmay also deactivate the second SCell.

Described herein are example methods related to the reception ofactivation/deactivation control signaling.

In one scenario, it may be desirable to trigger additional WTRUprocedure(s) upon activation/deactivation of a concerned SCell. This maybe achieved either implicitly from the change in activation/deactivationstate of the concerned SCell, or explicitly by including additionalsignaling information inside the activation/deactivation command.

Example methods related to the reception of activation/deactivationcontrol signaling may be any of the following: upon reception by theWTRU of the control signaling, the WTRU may activate/deactivate/releasepreviously configured dedicated DL resources for the SCell such assemi-persistent scheduling (SPS) resources; the WTRU may trigger areport of the WTRU's power headroom for the CC upon activation of theCC; the WTRU may trigger internal reporting of HARQ failure for a HARQprocess to upper layer(s), (e.g., to the radio link control (RLC)), uponexplicit or implicit deactivation of a SCell with configured uplinkresources using the services of the HARQ entity controlling the HARQprocess to lower the latency of retransmissions; the WTRU may determinethe transmission mode to use for UL control signaling, whichtransmission format may depend on the number of configured, (oralternatively active), SCell(s), e.g., the transmission mode of the HARQfeedback and/or the CQI/PMI/RI information on the PUCCH; the WTRU maydetermine the resources for acknowledgement of control signaling forSCell (de)activation; the WTRU may determine the CC behavior uponactivation, e.g., which resource and in which CC the HARQfeedback/CQI/PMI/RI may be sent for PDSCH transmissions and whether ornot the WTRU may monitor PDCCH in the newly activated SCell; the WTRUmay determine the MAC WTRU behavior upon reconfiguration, including theremoval of at least one SCell; the WTRU may determine MAC WTRU behaviorupon deactivation of at least one SCell; the WTRU may determine whetheror not cross-carrier scheduling is used for CCs upon activation; or theWTRU may determine the size of the control region of a SCell beingactivated, (e.g., information typically found by the WTRU on the PCFICHwhich allows the WTRU to determine the location in time of the firstsymbol of the PDSCH), especially for a SCell DL for which cross-carrierscheduling is used.

Additional example methods related to the reception ofactivation/deactivation control signaling may be used, in particular ifeach configured UL CC is associated with one or more DL CC(s), e.g., by“SIB2-linking”, “Dedicated-linking”, “HARQ feedback-linking”,“Scheduling-linking” or “Band-linking” as described above, or the use ofcontrol signaling between the base station and the WTRU across differentCCs. The methods described herein may be used by a WTRU upon receptionof control signaling from the base station for the purposes describedbelow. The reception of the control signaling may trigger WTRUprocedures for obtaining/maintaining the WTRU's UL TA needed to performtransmissions on UL resources corresponding to the serving cell and maytrigger WTRU procedures for obtaining/maintaining the WTRU's SI neededto access UL resources corresponding to the CC, and/or may trigger WTRUprocedure to access DL resources of one or more DL CC(s) associated withthe UL CC. It may also be used to trigger WTRU procedures foractivating/deactivating/releasing previously configured dedicated ULresources for the UL CC such as PUCCH resources allocated for CQI, PMI,RI, and SR; SPS resources, or SRS resources.

For example, a WTRU configured with at least one SCell may, uponactivation of the concerned SCell for which the applicable TAT is notrunning, initiate transmission of a random access procedure on a PRACHresource of the concerned SCell.

For example, a WTRU configured with at least one SCell may not transmitSRS for the concerned SCell when the concerned SCell is deactivated.

For example, a WTRU configured with at least one SCell may not reportCQI, PMI, or RI for the concerned SCell when the concerned SCell isdeactivated.

For example, a WTRU configured with at least one SCell may not transmiton PUSCH for the SPS resources when the concerned SCell is deactivated,if at least one SPS resource is configured for the concerned SCell.

For the example methods further described herein, the control signalingreceived by the WTRU from the base station may be L1, (e.g., PDCCH), L2(e.g., MAC), or L3, (e.g., RRC), messages. A message may apply to asubset of, (e.g., one or more), configured SCells. The signaling may bereceived on a DL CC which is already active, e.g., on the PCell DL.Alternatively, the signaling may be received on a DL CC which is alreadyactive e.g. on any active serving cell, and applied to a differentSCell.

In another scenario, it may be desirable to improve the robustness ofthe (de)activation procedure to ensure a coherent view of the availableresources from both the base station and the WTRU's perspective. Thismay be achieved by transmitting explicit acknowledgement of theactivation/deactivation command, e.g., using a similar mechanism as the“HARQ feedback” on the PUCCH.

Another aspect of the described methods address how a WTRU configuredwith at least one SCell, upon reception of control signaling foractivation/deactivation of at least one SCell for which anacknowledgement may be sent, may determine which resource to transmitthe acknowledgement onto.

Described herein are example methods where upon reception of the controlsignaling for which the WTRU may be expected to transmit feedback (e.g.,acknowledgement), the WTRU may determine that feedback may betransmitted in a resource (e.g., format and/or location and/or channelcoding) of the control region (e.g., in the PUCCH region) of the UL CCif the UL CC is configured for all HARQ feedback transmissions (e.g.,PCell UL), the UL CC is associated (e.g., paired) to the DL CC on whichthe control signaling was received, and/or the UL CC is configured forthe purposes of transmitting feedback. In addition, the location on theabove UL CC corresponds to one of: a resource (e.g., location) computedbased on the first CCE of the PDCCH which indicated the presence of thecontrol signaling, one of a set of configured (e.g., RRC) resources(e.g., format and/or locations and/or channel coding), indicated by anindex that may be provided in the control signaling; or in combinationwith any of the above, a resource (e.g., location) offset from the PUCCHregion of the UL CC, where the offset may be derived from an index tothe associated DL CC.

Another aspect of the described methods address how a WTRU configuredwith at least one SCell, upon reception of control signaling, maydetermine whether or not a SCell may be activated/deactivated.

The described examples herein may include the case where at least partof the control signaling may be received by the WTRU as configurationfor multicarrier operation even when the initial SCell state upon(re)configuration is “deactivated”. In particular, the initial valuesfor the parameters relating to the aspects of a WTRU's reception on aSCell DL, for example, may be at least one of: a PCFICH value or CFIindicating the size of the control region; an indication of whether ornot CFI may be used; a TAT value or TAC; one or more RNTI(s) for theWTRU, e.g. a SCell-specific C-RNTI, a CA-RNTI, a A-RNTI_i as describedabove). Moreover, the initial values for the parameters relating to theaspects of a WTRU's transmission on a UL CC, for example, may be atleast one of a dedicated HARQ feedback resource and/or an index to ameasurement configuration. This may be included in the WTRU'sconfiguration of corresponding said CCs.

Described herein are scenarios and methods related to how the WTRUconfigured with at least one SCell determines the size of the controlregion on a given SCell DL affected by activation and deactivation ofSCells.

Before the WTRU may decode the PDSCH on a newly activated SCell, it mayfirst determine the location of the first symbol of the PDSCH. Whenthere is no cross-scheduling for a given serving cell, the WTRUtypically decodes the Physical Control Format Indicator Channel(hereafter PCFICH). The PCFICH may be found at specific location(s)known to the WTRU and its value may change in any subframe. The PCFICHindicates the size of the control region of the DL CC in which it iscarried (e.g., whether it is 0, 1, 2, 3, or 4 symbols). Once the WTRUknows the size of the control region, it may implicitly determine thelocation of the first symbol of the PDSCH. When cross-carrier schedulingis used, the WTRU may not have the capability to decode the PCFICH forthe scheduled resources, or the PCFICH may not be available, and thusmeans for the WTRU to determine the size of the control region for agiven serving cell (e.g. a configured SCell) may be desirable.

The information in the control signaling received by the WTRU configuredwith at least one SCell may also include a Control Format Indicator(CFI). The WTRU may use the CFI to determine the size of the controlregion of a DL CC. In particular, a DL CC which is being activated maybe a secondary CC of the WTRU. Restated, when the WTRU is configuredwith cross-carrier scheduling, the WTRU may be provided with thestarting OFDM symbol of PDSCH for the concerned SCell within the RRCcontrol signaling that configures the concerned SCell and/or thatconfigures the WTRU for cross-carrier scheduling, i.e. with a value thatthe WTRU uses when the concerned SCell is activated which valueindicates the size of the control region of the SCell DL of theconcerned SCell.

Described herein are example methods for handling cross-carrierscheduling. For a UL or a DL CC, for the purpose of cross-carrierscheduling, (e.g., PDSCH in the case of a DL CC and PUSCH in the case ofa UL CC), of the CC, (or multiple CCs in case the control signalingactivates more than one SCell at once), the WTRU determines whichPDCCH(s) corresponding to which DL CC(s) may provide control signaling,(e.g., DL assignments, UL grants, other control messages, e.g., powercontrol commands), for the CC using at least one of the followingmethods.

In one example, the WTRU may determine that the PDCCH of the SCell DLfor which the control signaling for SCell activation is applicable,(i.e., the concerned SCell), may be used to schedule the concernedSCell, (i.e., similar behavior as for a Rel-8 serving cell). For thecase of a SCell DL, this may be based on an explicit indication ofwhether or not the WTRU may decode the PDCCH for the concerned SCell DL.In another example, the WTRU may determine that the PDCCH of the DL CCfrom which the control signaling for SCell activation is received may befurther used to schedule the concerned SCell (i.e., cross-carrierscheduling from the DL CC on which the activation command was received).In another example, the WTRU may determine that the PDCCH of a DL CC(e.g. the PDCCH of the PCell) may be further used to schedule theconcerned SCell based on a configuration received for the concernedSCell, (e.g., RRC configuration).

For example, a WTRU configured with at least one SCell may determine,upon activation of a concerned SCell, that the PDCCH of the concernedSCell DL may be used for the reception of control signaling, (e.g.DCIs), for scheduling based on a configuration of the concerned SCell,such as received in a RRC message that includes a configuration of theconcerned SCell for the dedicated physical radio resources, e.g., aPhysicalConfigDedicatedSCell IE, which included a configuration for thecross-carrier scheduling of the SCell, e.g. aCrossCarrierSchedulingConfig IE, indicating that cross-carrierscheduling is not used for the concerned SCell. Additionally, the WTRUmay also determine the size of the control region based on a parameter,e.g., a value indicating the first symbol of the PDSCH of the concernedSCell, received in the RRC message that configured the concerned SCelle.g., inside the configuration for the cross-carrier scheduling of theSCell. Alternatively, if the configuration includes an identity of theserving cell from which the concerned SCell is scheduled, the WTRU maydetermine that the PDCCH of the DL CC of said indicated serving cell maybe used to schedule transmissions for the concerned SCell.

The WTRU may also deactivate a SCell if the WTRU receives signaling fromthe network indicating that a handover may be performed. For example,this may happen upon reception of the RRCConnectionReconfigurationmessage including the mobilityControllnfo IE. The WTRU may alsodeactivate a SCell if the WTRU starts a handover timer such as the T304timer.

In another example, the WTRU configured with at least one SCell maydeactivate all configured SCells following the processing of controlsignaling indicating that the WTRU shall perform a handover to anotherserving cell, e.g., following the processing of a RRC reconfigurationmessage with the mobility control information element. A SCell of theWTRU's configuration may then be first activated by reception ofactivation/deactivation control signaling which control signalingincludes an explicit identity of the SCell(s) for which the controlsignaling applies e.g., by the reception of an activation/deactivationMAC CE activating one or more of the deactivated SCell(s).

Described herein are example methods that follow an error condition. TheWTRU may deactivate a concerned SCell if at least one of the followingconditions occurs. The WTRU may deactivate a concerned SCell if the WTRUinitiates the RRC connection re-establishment procedure or if the WTRUstarts a timer T311 (initiation of RRC Connection Re-establishmentprocedure). For example, if the specific CC for which radio link failure(RLF) is detected is a PCell of the WTRU configuration, as a consequencethe WTRU deactivates all configured/active SCell(s) upon RLF for atleast said PCell. Restated, the WTRU configured with at least one SCellmay deactivate all configured SCells when the WTRU initiates the RRCconnection re-establishment procedure after it determines downlinkand/or uplink RLF for the PCell. The WTRU may also deactivate aconcerned SCell if the WTRU may detect RLF in a specific CC undercertain situations. For example, if the specific SCell is a SCell of theWTRUs configuration, the WTRU may deactivate the specific SCell after itdetermines downlink and/or uplink RLF for said specific SCell. In all ofthe above cases, the configuration of the deactivated SCell(s) may beremoved from the WTRU's configuration. In another example, the specificCC for which RLF is detected may be a SCell of the WTRU configuration,including where at least said SCell is deactivated upon RLF detectionfor the SCell. In this case, the configuration of the deactivatedSCell(s) may be removed from the WTRU's configuration.

The WTRU may also deactivate a concerned SCell if the WTRU fails areconfiguration procedure. For example, a deactivation may occur whenthe failed reconfiguration may have been performed due to the receptionof RRC signaling from the base station (e.g., aRRCConnectionReconfiguration), the reconfiguration may have beenapplicable to the concerned SCell, or the reconfiguration may have beenapplicable to a PCell.

Described herein are scenarios and methods related to transmissions bythe WTRU on configured downlink and/or uplink resources affected byactivation and deactivation of SCells. Such resources are configured fora WTRU by dedicated signaling and may include periodic dedicatedsounding reference signal (SRS) transmission resources, UL and/or DL SPSresources, periodic transmission of CQI, PMI, RI either on a dedicatedPUCCH resource allocation or on a PUSCH transmission, a dedicatedresource for SR transmission on PUCCH, a configuration for transmissionof HARQ ACK/NACK feedback on one or more PUCCH resources, and the like.

In one scenario, the WTRU may be configured with a dedicated radioresource configuration when it has a connection to the base station.When SCells are activated and later deactivated, how to handle dedicatedresources may need to be addressed to avoid a WTRU creating interferencewith other WTRUs in the concerned serving cell for which dedicatedresources may be configured and to minimize additional signalingoverhead.

The described methods also address how a WTRU configured with at leastone SCell, upon activation/deactivation of a given subset, (i.e., one ormore), of SCell(s), may determine whether or not it maystart/stop/release configured dedicated UL resources, e.g., PUCCH forCQI/PMI/RI, SRS or SPS resources and perform the procedure tostart/stop/release configured UL resources, if needed.

The described methods also address how a WTRU configured with at leastone SCell, upon reception of control signaling foractivation/deactivation of at least one concerned SCell, may determinethe resources and the respective UL CC on which to transmit HARQfeedback as well as whether or not it may monitor the PDCCH associatedwith the activated concerned SCell(s).

When the WTRU activates a concerned SCell, for the purpose of handlingconfigured UL resources for the concerned SCell, the WTRU may startusing the configured UL resources if at least one of the followingconditions occurs: if the control signaling received includes anindication to activate configured UL resources corresponding to theconcerned SCell, (e.g., for SPS, for SRS and on the PUCCH for CQI, SR,PMI, RI); if the TA applicable to the UL resources associated with theconcerned SCell is valid; or if the control signaling is received on aPDCCH and scrambled using a specific RNTI, (e.g., A-RNTI_2).

The described methods also address how a WTRU, upon deactivation of agiven subset, (i.e., one or more), of SCell(s), may determine whether ornot it may release configured dedicated DL resources, e.g., SPSresources and perform the procedure to release configured DL resources,if needed.

When the WTRU activates a concerned SCell, for the purpose of handlingconfigured DL resources for the concerned SCell, the WTRU may startusing those resources if one of the following conditions occurs: if thecontrol signaling received includes an indication to activate configuredDL resources corresponding to the concerned SCell (e.g., for SPS) or ifthe control signaling is received on PDCCH and scrambled using aspecific RNTI (e.g., A-RNTI_3).

When the WTRU deactivates a concerned SCell, for the purpose of handlingof configured DL resources for the configured SCell, the WTRU mayrelease the configuration for those resources on the occurrence of anyof the following situations. The WTRU may release if the controlsignaling received includes an indication to release configured DLresources corresponding to the concerned SCell (e.g., for SPS) or if thecontrol signaling is received on PDCCH and scrambled using a specificRNTI (e.g., A-RNTI_5).

In another example, the control signaling may contain an indication ofwhether or not the WTRU may resume using previously configured UL/DLresources, e.g., PUCCH resources for ACK/NACK, PUCCH resources forCQI/PMI/RI/SR, SRS, SPS grant and/or assignment, and the like orportions thereof. It may be an index to an item in a set of thepreviously configured UL/DL resources. For example, the WTRU may use aconfigured resource of a SCell being activated, and/or the WTRU may usea configured resource of a given serving cell, (e.g., the PCell), upondeactivation of a SCell.

In another example, the WTRU may stop using a configured resource of aSCell being deactivated, and/or the WTRU may stop using a configuredresource of a given serving cell, (e.g., the PCell), upon deactivationof another SCell.

When the WTRU deactivates a concerned SCell, for the purpose of handlingof configured UL resources for the concerned SCell, the WTRU may releasethe configuration for any UL resources for SRS, for CQI/PMI/RI/SR onPUCCH and for SPS on the occurrence of any of following situations. TheWTRU may release the configuration if the control signaling receivedincludes an indication to release UL resources for SRS and CQI/PMI/RI/SRon PUCCH and for SPS for the concerned SCell. The WTRU may release theconfiguration if the control signaling is received on PDCCH andscrambled using a specific RNTI, (e.g., A-RNTI_4). The WTRU may releasethe configuration when the TA applicable to the UL resources of theconcerned SCell are no longer valid, (e.g., corresponding TAT expiresafter deactivation), following deactivation.

Described herein are further example methods for handling soundingreference signals (SRS).

In another scenario, the base station may configure a WTRU-specificperiodic SRS resource for SRS transmission on the radio resources of aUL CC. On a condition that there would be no explicitactivation/deactivation for the SRS resources e.g., based on the stateof the PUSCH of a UL CC, it may be desirable to have methods to avoidtransmission of SRS while the WTRU is not active in UL transmissions onPUSCH. Restated, if the activation/deactivation control signaling is notapplicable to UL CCs, a mechanism to suspend periodic transmissions onconfigured SRS resources of said UL CC may be desirable.

The described methods also address how a WTRU configured with at leastone SCell, while PUSCH transmissions are not active in a given SCell UL,may determine whether or not it may transmit SRS on a configuredperiodic resource (or resources).

For a UL CC, for the purpose of determining whether or not to transmitSRS on a configured SR resource in a given UL CC, the WTRU start (orcontinue) transmission of SRS in the UL CC using the configured SRSresources. In particular, the WTRU may start, or restart if alreadyrunning a timer (e.g., SRS-InactivityTimer): upon (re)configuration ofthe UL CC not removing the UL CC; upon reception of a UL grant for aPUSCH for the UL CC; upon a PUSCH transmission on the UL CC; upon atrigger or transmission of a SR and/or a BSR, which may be incombination with the WTRU's buffer reaching a configured threshold; uponthe WTRU buffers reaching a configured threshold; or upon explicitsignaling, e.g., L1 PDCCH or L2 MAC CE.

The WTRU may then transmit SRS in the UL CC using the configured SRSresources for a predefined time following the occurrence of one of theabove events. That is, the transmission is stopped after a specificperiod of UL inactivity for the CC. In one embodiment, this may beimplemented by transmitting SRS in the UL CC using the configured SRSresources and stopping transmission of SRS in the UL CC when the timer,e.g., SRS-InactivityTimer, expires.

When the WTRU deactivates a concerned SCell, the WTRU may stop any ULtransmissions (UL-SCH, PUSCH, SRS) for the deactivated SCell UL after atime t, (where t is a positive number), following the successfuldecoding of the control signaling.

Described herein are scenarios and methods related to monitoring ofdownlink control signaling by the WTRU affected by activation anddeactivation of SCells.

The described methods may also address how a WTRU, upon reception ofcontrol signaling for (de)activation of at least one SCell, maydetermine which DCI format(s) it may monitor on a given PDCCH.

When the WTRU activates a concerned SCell, the WTRU may start receivingthe PDSCH and, if the concerned SCell is configured for PDCCH reception,start monitoring PDCCH for grants and assignments, (e.g. scrambled byC-RNTI, SI-RNTI, P-RNTI, M-RNTI, or the like), on DL resourcesassociated with the concerned SCell.

When the WTRU activates a concerned SCell, if the WTRU is configured forcross-carrier scheduling for the concerned SCell on the PDCCH of anotherserving cell, and if the WTRU has a configured WTRU-specific PDCCHSearch Space (SS) for reception of the scheduling control informationapplicable to the concerned SCell and/or if the WTRU receives in theactivation command an identity of the PDCCH SS, (e.g. a PDCCH SSID),corresponding to the concerned SCell, then the WTRU may start decodingPDCCH in the search space corresponding to the concerned SCell, (e.g.,corresponding to the SSID), for the DCI formats applicable to theconcerned SCell DL and, if configured, may start decoding DCI formatsapplicable to the associated/linked SCell UL. This may occur, forexample, for the case where the PDCCH used for cross-carrier schedulingcorresponds to the PCell DL or for the case where the PDCCH used forcross-carrier scheduling implicitly corresponds to the DL CC on whichthe control signaling for activation was received by the WTRU.

In another example, the control signaling may contain an indication inthe control signaling applicable to a SCell DL, whether or not the WTRUmay decode the PDCCH in the SCell DL.

When the WTRU deactivates a concerned SCell, the WTRU may stop receivingPDSCH and stop monitoring PDCCH, if configured for PDCCH reception), forgrants and assignments, (scrambled by C-RNTI, SI-RNTI, P-RNTI, M-RNTI,or the like), on DL resources associated with the concerned SCell. TheWTRU may, based on L3 measurement configuration and/or CQIconfiguration, continue to perform the related measurements and otherradio link maintenance tasks such as periodic monitoring of SI and/orpaging at specific occasions for the concerned SCell.

When the WTRU deactivates a concerned SCell, if the WTRU is configuredfor cross-carrier scheduling for the concerned SCell, and if the WTRUhas a configured WTRU-specific SS for the scheduling control informationapplicable to the concerned SCell on the PDCCH of a different servingcell, the WTRU may stop decoding PDCCH in the PDCCH search spacecorresponding to the concerned SCell, (e.g., corresponding to the SSID).For example, a WTRU configured with at least one SCell may not monitorthe PDCCH of a deactivated SCell and may not receive any downlinkassignments or uplink grants associated to a deactivated SCell.

When the WTRU activates or deactivates a concerned SCell, the WTRU mayalso change the formats of the DCIs it monitors on PDCCH. Ifcross-carrier scheduling is used, the WTRU may start decoding the DCIformats accordingly, (e.g., DCI formats with the CCIF indicator), forthe number of assignments and grants possible given the number of activeserving cells scheduled by a given PDCCH. If different transmissionmodes are supported on different activated SCells for which the WTRUmonitors assignments and grants in a given PDCCH, the WTRU may startdecoding the DCI formats accordingly, e.g., the WTRU may decode allformats for each supported transmission mode for the number ofassignments and grants possible given the number of active SCellssupporting each mode. This may be done in the subframe in which the WTRUreceived the control signaling for activation/deactivation of theSCell(s), after a fixed amount of time, (e.g., a WTRU processing timesuch as 4 ms), from the subframe in which the WTRU received the controlsignaling for activation/deactivation of the SCell(s), or after a fixedamount of time from the subframe in which the WTRU transmitted anacknowledgement of the control signaling.

When the WTRU activates or deactivates a concerned SCell, for thepurpose of decoding DL control information, (e.g., PDCCH), the WTRUdetermines at least one of the following for a given PDCCH: which DCIformat(s) to decode; which physical resources, (e.g., control channelelements); and how many decoding attempts to perform. The above PDCCHdetermination may be based on whether or not the PDCCH of the DL CC,(e.g. the PCell DL), supports cross-carrier scheduling to at least oneother CC, (e.g., one or more SCell(s)). It may also be based on thenumber of activated SCell UL(s) and SCell DL(s), and their respectivetransmission modes, (i.e., which DCI format corresponds to theirtransmission mode), for which the PDCCH may carry a DL assignment or anUL grant. Alternatively, it may be based on whether or not the DCIformat uses the additional CCIF field, or special codepoints. Forexample, if one CC supports spatial multiplexing and another CC does noton a DL CC whose PDCCH supports scheduling for both CCs, the WTRU maydecode against format 1 and format 2. In addition, once the WTRU findsthe maximum possible number of DL assignments for a given DCI format, itmay stop decoding against this format.

Described herein are scenarios and methods related to handling ofongoing transmissions affected by activation and deactivation of SCells.

In one scenario, handling of ongoing transmissions for multiple SCellsupon deactivation may be affected. Deactivation of a SCell may occurwhile one or more uplink transmissions on the SCell UL are stillongoing. This may abort the ongoing transmission(s) and introduceadditional transmission delays by relying on higher layer detection ofthe failed transmission and initiating a retransmission. Deactivation ofa SCell may occur while one or more downlink transmissions on the SCellDL have not yet completed.

The described methods also address how a WTRU configured with at leastone SCell, upon deactivation of a given subset, (i.e., one or more), ofSCell(s), may determine whether or not it may inform upper layers,(e.g., RLC), of a HARQ failure for a given MAC service data unit (SDU)(i.e., RLC PDU), i.e., perform a local NACK from MAC to RLC, for auplink HARQ process of a given SCell; and perform the procedure toinitiate retransmission of the RLC PDU, if needed.

When the WTRU deactivates a concerned SCell, for the purpose of handlingHARQ processes that have not yet completed their (re)transmissions upondeactivation of the SCell UL using the services of the correspondingHARQ entity, e.g., for HARQ processes that still have data in theirrespective HARQ buffer and that are either suspended, (e.g., a HARQ ACKon PHICH was last received), or have ongoing retransmissions, (e.g., aHARQ NACK on PHICH was last received), if the HARQ process has data inits buffer, the WTRU may indicate to upper layers, (e.g., RLC), thattransmission for the corresponding MAC SDU(s) has failed, (i.e., for thecorresponding RLC PDU(s)), and flush the HARQ buffer.

When the WTRU deactivates a concerned SCell, for the purpose of handlinga HARQ process state for the concerned SCell, the WTRU may set new dataindicators (NDIs) to 0 for all UL HARQ and/or flush the DL HARQ buffers,(i.e., the next transmission is considered a new transmission).

For example, when a WTRU configured with at least one SCell deactivatesa concerned SCell either explicitly e.g., when the WTRU receives anactivation/deactivation command such as an Activation/Deactivation MACCE deactivating the concerned SCell, or implicitly e.g., following theexpiration of a deactivation timer, the WTRU may flush all HARQ buffersassociated with the concerned SCell.

Described herein are scenarios and methods related to the power headroomreporting procedure by the WTRU affected by activation and deactivationof SCells.

A WTRU's power control may be performed per UL CC to compensate forslow-varying channel conditions. Some of the power control parameterssuch as Transmit Power Control (TPC), DL path loss measurements, andoffsets may be common to more than one UL CC.

In LTE R8/9, the power headroom reporting procedure may be used toprovide the serving eNB with information about the difference betweenthe nominal WTRU maximum transmit power for UL-SCH transmissions. ULpower control in LTE Release 8 (R8) may be based on a combined open loopand closed loop power control mechanism. The open loop component may bebased on pathloss (PL) estimation which is based on the WTRU'smeasurements of Reference Signal Received Power (RSRP) in the DL CC usedas the Path Loss (PL) reference and the known transmit power of the DLReference Signal (RS), which value is typically broadcasted as systeminformation. The pathloss estimation may be used by the WTRU todetermine uplink transmit power, and this estimation is based on a DL CCwhich is herein referred to as the PL reference. The closed loopcomponent may be based on direct control of WTRU transmit power by meansof explicit power control commands (TPC) transmitted on the PDCCH.

For LTE Release 10 (R10), when the WTRU operates with at least oneSCell, a SCell UL may be configured with a PL reference for the purposeof uplink power control. For example, the PL reference of a SCell UL maybe a PCell DL of the WTRU's configuration, or the PL reference of aSCell UL may be configured as part of the WTRU's configuration (e.g.,one per frequency band).

In LTE R10, when the WTRU is configured with at least one SCell, a powerheadroom report may consist in either the power headroom value for atransmission corresponding to the UL-SCH in a given serving cell, hereinreferred as PHR Type 1, or the power headroom for transmissions on thePUCCH and the UL-SCH for the PCell, herein referred as PHR Type 2. Thedefinitions of Power Headroom Type 1 and Type 2 are as shown in Table 1.

TABLE 1 5.1.1.2 Power headroom There are two types of UE power headroomreports defined. A UE power headroom PH valid for subframe i for servingcell c. Type 1: PH_(c)(i) = P_(CMAX,c) − {10log₁₀(M_(PUSCH,c)(i)) +P_(O)_PUSCH,c(j) + α_(c)(j) · PL + Δ_(TF,c)(i) + f_(c)(i)} [dB] where,P_(CMAX,c), M_(PUSCH,c)(i), P_(O)_PUSCH,c(j), α_(c)(j)., PL, Δ_(TF,c)(i)and f_(c)(i) are defined in section 5.1.1.1. Type 2:${{PH}_{c}(i)} = {P_{{CMAX},c} - {10{{\log_{10}\begin{pmatrix}{10^{{({{10{\log_{10}{({M_{{PUSCH},c}{(i)}})}}} + {P_{{O\_{PUSCH}},c}{(j)}} + {{\alpha_{c}{(j)}} \cdot {PL}} + {\Delta_{{TF},c}{(i)}} + {f_{c}{(i)}}})}/10} +} \\10^{{({P_{0{\_{PUCCH}}} + {PL} + {h{({n_{CQI},n_{HARQ}})}} + {\Delta_{F\_{PUCCH}}{(F)}} + {g{(i)}}})}/10}\end{pmatrix}}\lbrack{dB}\rbrack}}}$ where, P_(CMAX,c), M_(PUSCH,c)(i),P_(O)_PUSCH,c(j), α_(c)(j) Δ_(TF,c)(i) and f_(c)(i) are the primary cellparameters as defined in section 5.1.1.1 and P_(O)_PUCCH, PL, h(n_(CQI),n_(HARQ)), Δ_(F)_PUCCH(F) and g(i) are defined in section 5.1.2.1 Thepower headroom shall be rounded to the closest value in the range [40;−23] dB with steps of 1 dB and is delivered by the physical layer tohigher layers.

In one scenario, power headroom reporting for multiple SCell UL uponactivation may be affected. How the WTRU notifies the base station ofthe WTRU's power headroom for a given SCell UL upon activation may needto be addressed to ensure that the scheduling process in the basestation has suitable and up-to-date information from the WTRU.

The described methods also address how a WTRU configured with at leastone SCell, upon activation of a given subset, (i.e., one or more), ofSCell(s), may determine whether or not it may trigger the transmissionof a PHR for a given UL CC and perform the procedure to transmit a PHR,if needed.

When the WTRU activates a concerned SCell, for the purpose of reportingthe WTRU's power headroom for the concerned SCell, the WTRU may triggera PHR which reported PHR corresponds to the power headroom for the SCellUL corresponding to the concerned SCell if the control signalingreceived includes an indication to trigger PHR. Alternatively, a PHR maybe triggered if the power headroom requirement applicable to the SCellUL associated with the concerned SCell differs from that of any otheractive UL CCs (i.e., a valid power headroom value for the SCell UL maynot be inferred from that of another UL CC). Alternatively a PHR may betriggered if the number of activated SCell(s) changes. Restated, everyactivation of a concerned SCell may trigger a PHR, which PHR may includeat least a report for the concerned SCell and may also include a PHR forall configured and/or active serving cells.

For example, a WTRU configured with at least one SCell triggers a powerheadroom report for each activated serving cell with configured uplinkresources when the WTRU activates at least one SCell with configureduplink resources.

If a PHR has been triggered and is pending for transmission and if theWTRU has uplink shared channel (UL-SCH) resources for a newtransmission, the WTRU may report a valid PHR value applicable to theSCell UL corresponding to the concerned SCell by using one of followingmethods. In one method, a PHR may be reported inside a MAC PHR CE in aMAC packet data unit (PDU) transmitted on a UL-SCH resource of a SCellUL corresponding to the concerned SCell. In another method, the PHR maybe reported inside a MAC PHR CE in a MAC PDU transmitted on a UL-SCHresource of any UL CC for which the calculated PHR may be applicable. Inanother method, the PHR may be reported inside a MAC PHR CE in a MAC PDUtransmitted on a UL-SCH resource of any UL CC, where the MAC PHR CE mayinclude a CCIF indicating for which UL CC(s) the reported PHR value maybe applicable. Restated, when the WTRU is configured with at least oneSCell, if a PHR has been triggered and the PHR is pending in a subframefor which the WTRU has resources allocated for at least one newtransmission on any serving cell, the WTRU may transmit a MAC PHR CEincluding at least a power headroom value for the concerned SCell andmaybe a value for the PCell and all other SCell(s) that are activated insaid subframe.

In addition, when a PHR value is calculated for a UL CC usingmeasurements and/or estimates based on a DL CC, e.g., path lossestimation and/or RSRP measurements, the WTRU may consider any of the DLCCs associated with the UL CC for which the PHR is calculated.

The described methods also determine whether or not to include controlinformation. In one method, the WTRU determines, for each transportblock (TB) within a given TB subset, whether or not it shall includespecific control information, (e.g. MAC CE), based on thecharacteristics of the MAC CE for transmission in a given TTI.

Described herein are characteristics that may be related to the MAC CE.One characteristic may be whether or not the transmission of a MAC CE isspecific to a given CC, including the case where a TB for the CC isgranted for a transmission in this TTI and the MAC CE contains: 1)information, (e.g. PHR), which is applicable to said CC, or to a relatedsubset of CC(s); 2) information, (e.g. C-RNTI), which is related to anongoing procedure, (e.g. Random Access), applicable to said CC, (e.g. CCof the PCell), or to a related subset of CC(s); or 3) information, (e.g.BSR), which is expected to be transmitted only in a specific CC, (e.g.,CC of the PCell), or to a related subset of CC(s).

Another characteristic may be the relative priority of the MAC CE. Forexample, (similar to LTE MAC Rel-8), the WTRU may take into account thefollowing relative priority in decreasing order: 1)MAC CE for C-RNTI ordata from UL-CCCH; 2) MAC CE for buffer status report (BSR), withexception of BSR included for padding; 3) MAC CE for PHR; 4) data fromany logical channel (LCH), except data from UL-CCCH; or 5) MAC CE forBSR included for padding. For example, a PHR reporting the powerheadroom value, (either for PUCCH, PUSCH or both), calculated for agiven UL CC may be included only in the MAC packet data unit (PDU) of aTB that corresponds to said UL CC if said TB is granted for atransmission in this TTI. In another example, a BSR reporting the stateof the WTRU's buffer after all TBs of this TTI have been filled may beincluded in the MAC PDU of a TB that corresponds to a specific CC onlyif said TB is granted for a transmission in said CC, (e.g. the CC of thePCell).

Another characteristic may be the type, (including format and content),of the MAC CE. The WTRU may select a MAC CE type as a function of thecontained information. The WTRU may determine whether the MAC CEcontains information related to a PCC (or PCell) or related to a SCC (orSCell) of the WTRU's configuration. For the example of a MAC CE for PHR,the WTRU may select a MAC CE PHR type_2 if the content of the PHR isapplicable to a PCC (or PCell) of the WTRU's configuration. Otherwise aMAC CE PHR type_1 is selected for a SCC (or SCell).

In another instance, the WTRU may determine whether or not the MAC CEcontains information applicable to a first CC (either a PCC or a SCC)and the MAC CE is transmitted on the first CC. For example, when theWTRU transmits, on a TB of a second CC, a MAC CE with contentsapplicable to a first CC, the WTRU selects a MAC CE format that includesan explicit identification of the first CC, (either SCC/SCell orPCC/PCell). In other words, the identity of the first CC may be omittedin the MAC CE format included if it is included in a MAC PDU transmittedon the first CC. Alternatively, a MAC CE that does not include anexplicit CC identification may be used if the identity of first CC maybe derived based on the order of the MAC CE(s) in the MAC PDU. This maybe applicable for the case where more than one MAC CE for the samefunction, (but possibly of different type), may be included in the sameMAC PDU. For example, a WTRU may include multiple MAC PHR CEs, (one foreach configured and/or activated serving cell), in the same MAC PDUeither following the order in which the serving cells were configured,(e.g., by RRC), and/or following the explicit serving cell identityvalue, (e.g., a cell index), assigned to each serving cell or somethingsimilar.

Another characteristic may be the type(s) of physical channel, (e.g.PUSCH and/or PUCCH), for which the WTRU performs uplink transmission(s)in the subframe in which the MAC CE is transmitted. This may be possiblyonly transmission(s) in the same CC, (either SCC/SCell or PCC/PCell), onwhich the MAC CE is transmitted. For example, for a PHR for a first CC,(either SCC/SCell or PCC/PCell), the WTRU may select MAC CE PHR Type_1if the WTRU performs only a PUSCH transmission in said first CC or theWTRU may select MAC CE PHR Type_2 if the WTRU performs a PUCCHtransmission and a PUSCH transmission in said first CC.

Another characteristic may be the type(s) of physical uplink channel,(e.g. PUSCH and/or PUCCH), that may be used by the WTRU for uplinktransmission(s) in a first CC, although such transmission is notperformed by the WTRU in the subframe in which a MAC CE applicable tothe first CC is transmitted on an uplink transmission on a second CC. Inparticular, if the content of the PHR MAC CE may include a “virtual”power headroom value for a first CC, the WTRU may select a MAC CE PHRType_1 for CC(x) if the first CC is not configured for PUCCHtransmission. The contents may include a power headroom value derivedbased on a “virtual” PUSCH transmission. Otherwise, the WTRU may selectMAC CE PHR Type2 for the CC, where the contents may include a powerheadroom value derived based on a “virtual” PUSCH transmission and a“virtual” PUCCH value. A “virtual” power headroom value above refers,for the part related to a PUSCH transmission, to a value derived by theWTRU for a first CC although no PUSCH transmission is performed, thefirst CC in the subframe used for transmission of the corresponding PHRon a second CC. Such a value may for example be inferred from the powerthat would have been used by the WTRU given a specific modulation codescheme (MCS) and a specific number M of resource blocks (RBs), which MCSand M may e.g., be derived either from a fixed, (e.g. specified orconfigured), value also known to the eNB, or from the grantcorresponding to a previous transmission on said first CC. Similarly,for the part related to a PUCCH transmission, if applicable for a firstCC), it refers to a value derived based on a transmission using e.g., apre-determined format such as format la. In all of the above cases,PUSCH transmission may be used independently of whether or not thetransmission includes uplink control information (UCI) and/or data.

The WTRU, once it determines that it shall include control informationin a TB, may later take into account the size of the control informationwhen serving data from the LCH(s) for the TB subset.

When the WTRU determines whether or not control information should beincluded, the WTRU may also perform the above for the PCell and possiblyalso for each configured SCell, (and possibly also activated). Forexample, if for PHR reporting the WTRU may report “virtual” powerheadroom values for configured and activated serving cells when a PHR istriggered, the WTRU may determine which serving cells are configured andactivated and would include a PHR MAC CE for each of those serving cellin at least one TB.

Described herein are scenarios and methods related to the WTRU's uplinktiming alignment affected by activation and deactivation of Scells for aWTRU configured with at least one SCell.

A WTRU may be configured with at least one SCell UL, i.e., with one ormore set(s) of serving cells with configured uplink resources, for whichthe timing advance (TA) may differ from that of the PCell UL. Forexample, this may happen when two UL CCs each have one or more of thefollowing characteristics: different coverage areas, (e.g., based on CCband); different propagation characteristics, (e.g., based on pathloss); or different or multiple points of origin, (e.g., different eNBsand/or due to frequency selective receivers, COMP deployment scenarios,remote radio heads and the like).

In one scenario, the TA may differ between different SCell UL and thismay impact the WTRU's operation on multiple serving cell(s). This may betrue when the serving cells are not in the same frequency band or forcertain deployment scenarios (e.g., using repeaters or remote radioheads from the same base station). On a condition that a WTRU isconnected to the PCell, and that additional SCells may be configured and(de)activated on an as-needed basis, when the TAT applicable to aserving cell that is less used (and occasionally inactive) is notrunning, care should be taken upon (re)activation to ensure that theWTRU does not initiate UL transmissions before having proper timealignment or before having up-to-date system information (SI). How tohandle other dedicated UL/DL resources configured for the WTRU may alsoneed to be addressed.

The described methods also address how a WTRU configured with at leastone SCell, upon activation of a given subset (i.e., one or more) ofconcerned serving cell(s), may determine whether or not it may consideritself time-aligned, i.e., whether or not it may use the UL resources ina concerned SCell without creating unnecessary interference totransmissions of other WTRUs in that SCell; perform the procedure(s) togain UL time-alignment for at least one of the SCells in the subset;and/or maintain timing alignment for at least one of the SCell(s) in thesubset.

For illustrative purposes only, the methods described herein may beapplicable to a WTRU configured with at least one SCell, where the SCellhas configured uplink resources, that may be connected to a base stationand where a SCell may be initially activated by the base station or whenthe TAT corresponding to a SCell is shorter than the period under whichthe concerned SCell was inactive, (e.g., in which case the TAT may nothave been restarted and/or may have expired). Different UL CCs may havedifferent TA requirements based on, for example, frequency or PhysicalCell ID for the cell on the associated DL CC. The WTRU may have aconnection to a PCell of the base station (e.g., RRC_CONNECTED in LTE).

When the WTRU activates a concerned SCell, for the purpose ofmaintaining the UL timing alignment, the WTRU may perform RA using RACHresources corresponding to the concerned SCell UL under any one of thefollowing conditions: if the control signaling received includes anindication to trigger RA; if the TA applicable to the SCell UL resourcesassociated with the concerned SCell is not valid (e.g., correspondingTAT is not running); or if the control signaling is received on a PDCCHand scrambled using a specific RNTI (e.g., A-RNTI_0).

In one example, the control signaling may contain an indication(explicit, implicit, or both) of whether or not the WTRU may perform theRA procedure, by at least one of the following: using the resourcescorresponding to the SCell indicated by the CCIF; using the RA resources(RA preamble, PRACH mask) explicitly indicated in the control signalingfor activation/deactivation; and/or if the TAT corresponding to theSCell (or group thereof) is not running. For example, the WTRUconfigured with at least one SCell may initiate the random accessprocedure on RA resources of the concerned SCell upon activation of theconcerned SCell, in particular if the TAT corresponding to the concernedSCell is not running. Alternatively, the WTRU may initiate the randomaccess procedure on RA resources of another serving cell which sharesthe same Timing Alignment requirement than that of the concerned SCell.

When the WTRU activates a concerned SCell, for the purpose of applyingthe TA Command (TAC) received after the activation of the concernedSCell, the WTRU may apply the received TAC to the TA of the UL CCcorresponding to the DL CC on which the TAC was received or to the TA ofall UL CCs having the same TA requirements as the UL CC corresponding tothe DL CC on which the TAC was received.

In another example, the control signaling may contain a Time AlignmentCommand (TAC), which the WTRU applies to at least one of: a UL CCidentified explicitly in the control signaling using e.g., a CCIF; theSCell UL corresponding to the concerned SCell which is being activated;or a group of UL CCs having the same TA requirements. The specific groupmay be identified based on the UL CC identified as described above. Forexample, the WTRU may apply a TAC received on the PDSCH of the concernedSCell to the TA of said concerned SCell and, may be to the TA of anotheractivated SCell which shares the same Timing Alignment requirement thanthat of the concerned SCell.

When the WTRU configured with at least one SCell deactivates a concernedSCell, for the purpose of handling any RA procedure operating in theconcerned SCell, the WTRU may stop any ongoing RACH procedure for theconcerned SCell. Alternatively, the WTRU may discard any explicitlysignaled preamble (e.g., ra-Preamblelndex) and PRACH resource (e.g.,ra-PRACH-Masklndex), if any, and if applicable to the concerned SCell.Alternatively, the WTRU may also release, if any and if applicable tothe concerned SCell, the Temporary C-RNTI.

Described herein are example methods for handling MAC reconfiguration.For a SCell DL or a SCell UL, for the purpose of handling WTRU MACbehavior for a RRC (re)configuration including the removal (release) ofat least one SCell, the WTRU may: stop, if any, ongoing RACH procedurefor the removed component carrier; discard explicitly signaled preamble(e.g., ra-Preamblelndex) and PRACH resource (e.g., ra-PRACH-Masklndex),if any, and if applicable to the removed SCell; and/or release, if anyand if applicable to the removed SCell, Temporary C-RNTI.

The RRC (re)configuration of additional CCs may implicitly trigger theabove RA procedures, for the purpose of gaining TA in serving cells forwhich the WTRU has no valid TA. This may apply to initial configurationand/or to any reconfiguration of the serving cells. The RRC(re)configuration of additional SCell(s) may also implicitly trigger aPHR. This may apply to initial configuration and/or to anyreconfiguration of the serving cell(s).

Described are example methods and/or actions upon reaching the maximumnumber of transmission of attempts for scheduling requests (SR) on PUCCHthat may affect the configuration, activation and deactivation of SCellsfor a WTRU configured with at least one SCell.

For the purpose of handling the WTRU configured with at least one SCell,when the number, (SR_COUNTER), of transmission attempts for the SR onthe configured and valid PUCCH resource for the SR reaches, (orexceeds), the maximum value configured by the network, (e.g.,dsr-TransMax), the WTRU may deactivate all configured and activeSCell(s), if any. This may include deactivation of the CQI/PMI/RIconfiguration for the SCells. Alternatively, the WTRU may initiate arandom access and cancel all pending SRs, which may include initiatingthe random access on the UL resources of a configured SCell.Alternatively, the WTRU may clear any configured downlink assignmentsand uplink grants. Alternatively, the WTRU may release the configurationfor multicarrier operation, including at least one of the following: theSCell(s) configuration, (possibly only the UL SCell configuration); thePUCCH configuration for HARQ ACK/NACK transmissions; the PUCCHconfiguration for CQI/PMI/RI transmissions; or the PUCCH configurationfor SR transmissions. In effect, the above examples may result inimplicit deactivation or release of all SCells due to reaching themaximum number of SRs.

In one example method, the WTRU may release the entire multicarrierconfiguration, (i.e., SCell(s), PUCCH resources for HARQ A/N,CQI/PMI/RI, SR), as well as any configured assignments or grants, andrevert to single carrier R8 or R9 operation in the serving cellcorresponding to the PCell of the WTRU's multicarrier configuration. TheWTRU may then initiate a random access in said serving cell, (i.e. thePCell). Table 2 provides an embodiment of this example method.

TABLE 2 If an SR is triggered and there is no other SR pending, the UEmay set the SR_COUNTER to 0. As long as one SR is pending, the UE mayfor each TTI: if no UL-SCH resources are available for a transmission inthis TTI: if the UE has no valid PUCCH resource for SR configured in anyTTI: initiate a Random Access procedure (see subclause 5.1) and cancelall pending SRs; else if the UE has a valid PUCCH resource for SRconfigured for this TTI and if this TTI is not part of a measurement gapand if sr-ProhibitTimer is not running: if SR_COUNTER < dsr-TransMax:increment SR_COUNTER by 1; instruct the physical layer to signal the SRon PUCCH; start the sr-ProhibitTimer. else: notify RRC to releasePUCCH/SRS and the configuration for all SCell(s), if any; clear anyconfigured downlink assignments and uplink grants; initiate a RandomAccess procedure (see subclause 5.1) and cancel all pending SRs.

In another example, the WTRU may deactivate any activated SCell, (SCellDL(s) and SCell UL(s)), and release the configuration for the PUCCHresources related to multicarrier operation, (i.e., PUCCH resources forHARQ A/N, CQI/PMI/RI, SR), as well as any configured assignments orgrants, and perform a random access by selecting an available resourceon any UL CC of its multicarrier configuration. It may select the PCellUL. For SCell UL(s), if no explicit deactivation state is defined, theWTRU may ignore any received uplink grants at least until it receivescontrol signaling to reconfigure the multicarrier operation. Table 3provides an embodiment of the example method.

TABLE 3 If an SR is triggered and there is no other SR pending, the UEmay set the SR_COUNTER to 0. As long as one SR is pending, the UE mayfor each TTI: if no UL-SCH resources are available for a transmission inthis TTI: if the UE has no valid PUCCH resource for SR configured in anyTTI: initiate a Random Access procedure (see subclause 5.1) and cancelall pending SRs; else if the UE has a valid PUCCH resource for SRconfigured for this TTI and if this TTI is not part of a measurement gapand if sr-ProhibitTimer is not running: if SR_COUNTER < dsr-TransMax:increment SR_COUNTER by 1; instruct the physical layer to signal the SRon PUCCH; start the sr-ProhibitTimer. else: notify RRC to releasePUCCH/SRS; deactivate all activated SCell(s), if any; [ignore anyreceived uplink grant(s) for all configured UL SCC(s), if any, until RRCreconfigures the UE for multicarrier operation] clear any configureddownlink assignments and uplink grants; initiate a Random Accessprocedure (see subclause 5.1) and cancel all pending SRs.

Described herein are scenarios and methods related to radio linkmonitoring procedures affected by activation and deactivation of SCellsfor a WTRU configured with at least one SCell.

In one scenario, the base station may configure the WTRU with at leastone SCell in addition to the PCell. If the radio link quality of some orall of the serving cells deteriorates beyond some quality criteria, amechanism to increase the capability of the WTRU to either recover orimprove communication towards the system may be needed.

The described methods also address how a WTRU configured with at leastone SCell, upon detection of physical layer problems and/or detection ofa reduction in radio link quality below a certain threshold, mayimplicitly activate some or all of the configured SCell(s) and/ordisable power saving algorithms (e.g., discontinuous reception (DRX))for those SCell(s).

For a SCell DL, for the purpose of activating a SCell DL, the WTRU maymonitor and/or detect physical layer problems, such as poor reception ofsynchronization signals based on, for example, the occurrence of anumber of out-of-sync indications from the physical layer, (e.g., N310,a value that may be configured by the base station), or failure tocomplete a number of random access procedure(s), (where the value may beconfigured by the base station). The WTRU may also monitor and detectradio link quality falling below a certain threshold. For example,measurements, (e.g., CQI), may fall below a certain threshold, (forexample a value configured by the base station). The monitoring anddetecting actions may be performed for the: PCell; configured SCell(s),whether or not the SCell is active/inactive; or configured serving cellsincluding the PCell and whether or not the SCell is active/inactive.

The WTRU, upon detecting a physical layer problem or radio linkdegradation, may activate a first SCell DL and/or continuously monitorcontrol signaling (e.g., independently of power savings functions suchas DRX). These actions may be performed for the: PCell; configuredSCell(s), whether or not the SCell is active/inactive; or configuredserving cells including the PCell and whether or not the SCell isactive/inactive. These actions may be performed at least until the WTRUreceives from the base station an explicit deactivation for theSCell(s), wherein the explicit deactivation may be included in a radioreconfiguration message with or without the mobility control IE (i.e.,handover command or a specific amount of time (e.g., timer T310) haselapsed. Upon expiration of the specific amount of time (e.g., timerT310), the WTRU may initiate either a change of PCell (e.g., a handover,connection re-establishment, or a reconfiguration procedure) within theset of configured SCells, or a connection re-establishment procedure toa different cell.

The WTRU may deactivate a concerned SCell if a radio link monitoringtimer, such as timer T310, is running, and if the WTRU detectsconditions that lead to the detection of physical layer problems, radiolink quality does not rise above a certain threshold, and/or theconcerned SCell was in a deactivated state prior to the start of theT310 timer (i.e., prior to the detection by the WTRU of physical layerproblems).

When the WTRU deactivates a concerned SCell, the WTRU may stop receivingPDSCH and stop monitoring PDCCH if configured for PDCCH reception) forgrants and assignments (scrambled by C-RNTI, SI-RNTI, P-RNTI, M-RNTI, orthe like) on DL resources associated with the concerned SCell. The WTRUmay, based on L3 measurement configuration and/or CQI configuration,continue to perform the related measurements and other radio linkmaintenance tasks such as periodic monitoring of SI and/or paging atspecific occasions for the concerned SCell.

Described herein are scenarios and methods related to acquisition andmaintenance of System Information (SI) by the WTRU configured with atleast one SCell affected by activation and deactivation of SCells.

In another scenario, when a SCell is inactive, the WTRU may not berequired to periodically monitor the SI and it may not be desirable tohave the WTRU monitor for SI notification in the deactivated SCell atsome specific occasion. How the WTRU ensures that the SI is up-to-dateupon SCell activation may need to be addressed to ensure that the WTRUmay access the additional resources of the SCell.

Another aspect of the described methods address how a WTRU, uponactivation of a given subset (i.e., one or more) of SCell(s) with CA,may determine whether or not it is required to acquire/update SIpertaining to at least one SCell of the subset; and perform theprocedure(s) to acquire/update the SI.

When the WTRU activates a concerned SCell, for the purpose ofmaintaining valid SI for the concerned SCell, the WTRU may acquire SIfor the concerned SCell using known procedures for SI acquisition whenat least one of following conditions occurs: if the WTRU has no storedSI for the concerned SCell; if the control signaling received includesan indication to acquire SI; if the control signaling includes a valuetag indicating that the stored SI is no longer valid; or if the controlsignaling is received on a PDCCH and scrambled using a specific RNTI(e.g., A-RNTI_1).

In another example, the control signaling may contain an indication ofwhether or not SI pertaining to the second CC has changed, e.g., basedon a SI value tag of, for example, a 5-bit or a simple binaryindication. The value tag may represent a portion of the SI pertainingto the second CC, such as the portion that may be required to be validfor proper operation on this second CC as part of a multicarrierwireless system. In this case, such a value tag may be provided in theSI of the second CC, in addition to the existing value tag representingthe whole SI. Similarly, the binary indication may represent a change ofa portion of the SI.

In addition, when the WTRU may re-acquire the SI for the PCell, changein some of the SI information may impact operation on the SCells (ifconfigured and activated). For example, assuming the WTRU sends ULcontrol information (e.g., HARQ A/N, CQI, and the like) on the PUCCHresources of a single UL CC (e.g., the PCell UL), a change in the PUCCHconfiguration may impact the transmission of the control signaling.

The WTRU may also deactivate a SCell while the WTRU reacquires SI due toa change in SI. For example, if the SI only pertains to the PCell or ifthe SI is broadcasted only on the PCell. In another example, the SIchange may be related to a given item in the configuration (e.g., theconfiguration for PUCCH of the associated UL CC).

Described herein are scenarios and methods related to resourceallocation for the uplink HARQ feedback for downlink transmissions bythe WTRU affected by activation and deactivation of SCells.

A WTRU may transmit HARQ feedback for PDSCH transmissions received inany configured and active DL CC on the resources of a single UL CC,(e.g., on the PUCCH of the PCell). The applicable resource allocationmay be determined by the first control channel element (CCE) of thePDCCH for the corresponding PDSCH transmission. A WTRU may transmitCQI/PMI/RI for any configured CC on the resources of a single UL CC(e.g., on the PUCCH of the PCell). The applicable resource may beconfigured by RRC signaling.

In another scenario, the transmission mode for PUCCH signaling in a ULCC (e.g. the PCell UL) carries a fixed amount of information (i.e., theformat) given a fixed link budget and the format, for decoding purposes,may be known by the receiver. The WTRU may be configured to transmitHARQ ACK/NACK (A/N) feedback for concurrent PDSCH transmissions indifferent serving cells and/or CQI/PMI/RI feedback for multiple servingcells. The manner in which the WTRU transmits control information on thePUCCH may be dependent on the number of configured SCells/PDSCHs and/orthe number of serving cells for which the WTRU may report CQI/PMI/RI.While it may be possible for the base station to control the WTRU ULactivity on the PUCCH in a manner that makes the switch between theWTRU's PUCCH transmission mode to occur in a predictable manner (e.g.,by introducing a delay or a silent period for HARQ feedback on the PUCCHbetween reconfiguration/activation/deactivation of SCells), it may bedesirable for the WTRU to follow a clear behavior to avoid any possibleuncertainty regarding which format to use for a PUCCH transmission inany given subframe. The need for a clear synchronization point may beespecially relevant for the CQI/PMI/RI and the HARQ

Another aspect of the described methods address how a WTRU configuredwith at least one SCell, upon detection of a change in the number ofconfigured (alternatively active) SCell DL(s), (i.e., PDSCH), for whichit may be reporting HARQ feedback (e.g., on PUCCH) and/or other uplinkcontrol information such as CQI/PMI/RI in a single given UL CC, mayimplicitly change a transmission mode (format) for the UL controlsignaling either in the subframe from which the reconfiguration isapplicable, in the subframe at which the number of the SCell DL(s) haschanged, or after an offset amount of time thereof (e.g., after 3 msprocessing time).

In another example, the control signaling may contain a configuration ofthe WTRU, or alternatively an index to said configuration. This mayinclude at least one of the following information. The information maybe a PUCCH configuration or an index thereto for at least one ofresources (e.g., format and/or location and/or coding) for HARQ A/Nand/or resources for CQI/PMI/RI. The information may also be a SRSconfiguration or an index thereto. The information may also be a SPSconfiguration or an index thereto, either for UL CC or DL CC or both.The information may also be a radio resource configuration, such as atransmission mode of a CC. For any of the above configurationinformation, the configuration information may be index to an item in aset of previously configured UL/DL resources.

The information may also be a configuration that may be applicable to atleast one of: the SCell UL corresponding to the concerned SCell that isbeing activated; the PCell UL corresponding to the PCell; or the UL CCor DL CC of another serving cell explicitly indicated in the controlsignaling.

In another example, the control signaling may contain an indication ofwhether or not the WTRU may use the PUCCH resources for HARQ feedback inthe UL CC corresponding to at least one of: the UL CC being associatedwith the serving cell in which the control signaling was received; theUL CC corresponds to the PCell; the UL CC being configured (e.g., RRC)for reporting of HARQ feedback for PDSCH transmissions on multiple DLCCs; or a set of PUCCH resources (e.g. format, locations and/or channelcoding) configured (e.g., by RRC) for example as an index to an item ina set of configured resources. For example, the WTRU may receive anindex to a set of indexes for the purpose of HARQ feedback resourceallocation.

For the purpose of selecting which transmission mode the WTRU may usefor the transmission of control signaling either on PUCCH or on PUSCH ona UL CC (e.g. the PCell UL), the WTRU may do the following. The WTRUdetermines if the WTRU is configured to report control signaling suchthat control information for one or more DL CCs may be included in thesame transmission format. The control signaling may be controlinformation for multiple serving cells and may be aggregated in the sametransmission format, the control signaling may be HARQ feedback for aPDSCH transmission, or the control signaling may be CQI/PMI/RI feedback.If the WTRU activates or deactivates at least one SCell DL, whichactivation/deactivation results in a different number of serving cellsfor which the WTRU reports control signaling in the same transmissionformat, the WTRU may change transmission mode for any combination ofCQI, PMI, and/or RI when reporting on PUSCH and/or on PUCCH if suchresources are configured for the WTRU) in the subframe in which the WTRUreceived the control signaling for activation/deactivation of theSCell(s) or after a fixed amount of time (e.g., a WTRU processing timesuch as 4 ms), from the subframe in which the WTRU received the controlsignaling for activation/deactivation of the SCell(s); or after a fixedamount of time from the subframe in which the WTRU transmitted anacknowledgement of the control signaling.

Described herein are scenarios and methods related to cross-carrierscheduling affected by activation and deactivation of SCells.

When a WTRU may be scheduled (either UL grants or DL assignments) onmultiple serving cells, the WTRU may either be configured to monitorPDCCH in each of the configured DL CCs, or it may be configured forcross-carrier scheduling.

Another aspect of the described methods address how a WTRU configuredwith at least one SCell, upon SCell activation, may determine whether ornot cross-carrier scheduling may be used for that SCell and/or whetherit may activate additional SCells for that purpose.

In another example, the control signaling may contain an indication inthe control signaling applicable to a CC, whether or not the WTRU maydecode the PDCCH in a DL CC used for cross-carrier scheduling of radioresources for said CC. This may include an identity of the DL CC usedfor cross-carrier scheduling of said CC.

In another example, the control signaling may contain an indication inthe control signaling applicable to a DL CC, whether or notcross-carrier signaling is applicable for the PDCCH of the DL CC. Thismay include an explicit indication and/or identity of whichWTRU-specific SS(s) the WTRU may decode the PDCCH for DL assignments(“PDCCH SSID”). In particular, this may include an index to an item of aWTRU-specific SS configuration, and/or a parameter to derive thestarting location of the WTRU-specific SS such as the number of CCEs forthe search space (SS) or a virtual identifier to use instead of the WTRUID used to derive a PDCCH candidate in the SS.

In another example, the control signaling may contain an indication inthe control signaling applicable to a UL CC, whether or notcross-carrier signaling is applicable for the PUSCH of the UL CC. Thismay include explicit indication and/or identity of which DL CC(s) mayprovide scheduling control information (i.e., PDCCH) for the CC. It mayinclude an explicit indication and/or identity of which WTRU-specific SSthe WTRU may decode the PDCCH for UL grants (“PDCCH SSID”). Inparticular, it may include an index to an item of a WTRU-specific SSconfiguration and/or a parameter to derive the starting location of theWTRU-specific SS such as the number of CCEs for the SS or an virtualidentifier to use instead of the WTRU ID used to derive a PDCCHcandidate in the SS.

In another example, the WTRU may receive in the RRC control signalingthat configures the concerned SCell and/or that configures the WTRU forcross-carrier scheduling, an indication of whether the concerned SCellis scheduled by the PDCCH on said concerned SCell or not, and if notpossibly also which serving cell signals the downlink and uplink grants,if uplink resources are configured, for the concerned SCell.

The applicability of the methods described herein may depend on thestate of the WTRU and/or base station. For example, method applicabilitymay depend on: whether or not the TAT applicable to the serving cell isrunning; whether or not the SCell UL has different TA requirements thanat least one other UL CC configured for the WTRU; whether or notdedicated resources (e.g., SPS, PUCCH, SRS) are configured for the SCellUL; whether or not dedicated resources (e.g., SPS) are configured for aDL CC associated with the UL CC; the association between one or more DLCC(s) with the UL CC, e.g., via mapping for HARQ feedback; whether ornot the power headroom reporting function is configured for the UL CC;and whether or not the HARQ process has data left in is its buffer(i.e., HARQ has not yet completed the transmission of the transportblock in its buffer). The examples described herein are generallyapplicable independently of whether or not DRX is configured and/orapplicable for the CC.

Although features and elements are described above in particularcombinations, one of ordinary skill in the art will appreciate that eachfeature or element can be used alone or in any combination with theother features and elements. In addition, the methods described hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable medium for execution by a computeror processor. Examples of computer-readable media include electronicsignals (transmitted over wired or wireless connections) andcomputer-readable storage media. Examples of computer-readable storagemedia include, but are not limited to, a read only memory (ROM), arandom access memory (RAM), a register, cache memory, semiconductormemory devices, magnetic media such as internal hard disks and removabledisks, magneto-optical media, and optical media such as CD-ROM disks,and digital versatile disks (DVDs). A processor in association withsoftware may be used to implement a radio frequency transceiver for usein a WTRU, UE, terminal, base station, RNC, or any host computer.

What is claimed is:
 1. A method implemented at a wirelesstransmit/receive unit, WTRU, for handling carrier aggregation,comprising: establishing a connection with a primary cell (PCell);configuring the WTRU with a secondary cell (SCell); receiving anactivation/deactivation medium access control (MAC) control element (CE)comprising fields for signaling activation/deactivation states formultiple SCells; determining the activation/deactivation state for theSCell using an identity of the SCell as an index to theactivation/deactivation MAC CE; activating or deactivating the SCellbased on the determined activation/deactivation state; triggering apower headroom report (PHR) responsive to activation of the SCell and ona condition that the SCell is configured for uplink transmission; andgenerating a MAC protocol data unit (PDU) including a PHR MAC CE toreport the triggered PHR in a next available transmission opportunitybased on a size of the PHR MAC CE and on condition that the WTRU hasallocated uplink resources and the triggered PHR is pending fortransmission.
 2. The method of claim 1, wherein the SCell is activatedon condition that the determined activation/deactivation state commandsan activation of the SCell.
 3. The method of claim 1, wherein the SCellis deactivated on condition that the determined activation/deactivationstate commands a deactivation of the SCell.
 4. The method of claim 1,further comprising: on a condition that the SCell is configured forreception of a physical downlink control channel, starting a monitoringof the physical downlink control channel in response to activation ofthe SCell.
 5. The method of claim 1, further comprising: receiving across-carrier scheduling configuration; and determining, from thecross-carrier scheduling configuration, a starting symbol of a physicaldownlink shared channel for the SCell.
 6. The method of claim 1, furthercomprising: responsive to deactivation of the SCell, stopping amonitoring of a physical downlink control channel for the SCell; andstopping receiving downlink assignments or uplink grants associated withthe SCell.
 7. The method of claim 1, further comprising: receiving across-carrier scheduling configuration; and determining, based on thecross-carrier scheduling configuration, a serving cell for receivingdownlink allocations or uplink grants for the SCell.
 8. The method ofclaim 1, further comprising: responsive to deactivation of the SCell,stopping a reporting of a channel quality indicator, a precoding matrixindex, or a rank indication for the SCell.
 9. The method of claim 1,further comprising: responsive to deactivation of the SCell, releasing asounding reference signal reporting configuration for the SCell.
 10. Themethod of claim 1, further comprising: releasing a configuration for theSCell responsive to an indication of a radio resource controllerconnection re-establishment.
 11. The method of claim 1, wherein theactivation/deactivation MAC CE includes a bitmap, and wherein each bitin the bitmap corresponds to, and indicates the activation/deactivationstates of, one of the multiple SCells.
 12. The method of claim 1,wherein the SCell is initially configured in a deactivated state. 13.The method of claim 1, wherein the SCell is configured using an SCellconfiguration received via dedicated signaling, and wherein the SCellconfiguration comprises the identity of the SCell and a radio resourceconfiguration that identifies configuration parameters for downlink (DL)and uplink (UL) resources of the SCell.
 14. The method of claim 1,wherein a deactivation timer is started or restarted responsive to theactivation/deactivation MAC CE signaling activation of the SCell. 15.The method of claim 14, wherein the activation/deactivation MAC CE isreceived prior to expiry of the deactivation timer.
 16. The method ofclaim 1, further comprising transmitting the MAC PDU at the nextavailable transmission opportunity.
 17. The method of claim 1, whereinthe PHR MAC CE includes a valid PHR value for at least the SCell.
 18. Awireless transmit/receive unit, WTRU, configured for carrieraggregation, comprising: a transceiver; and a processor in communicationwith the transceiver, wherein the processor is configured to: establisha connection with a primary cell (PCell); configure the WTRU with asecondary cell (SCell); receive an activation/deactivation medium accesscontrol (MAC) control element (CE) comprising fields for signalingactivation/deactivation states for multiple SCells; determine theactivation/deactivation state for the SCell using an identity of theSCell as an index to the activation/deactivation MAC CE; activate ordeactivate the SCell based on the determined activation/deactivationstate; trigger a power headroom report responsive to activation of theSCell, and on a condition that the SCell is configured for uplinktransmission; and generate a MAC protocol data unit (PDU) including aPHR MAC CE to report the triggered PHR in a next available transmissionopportunity based on a size of the PHR MAC CE and on a condition thatthe WTRU has allocated uplink resources and the triggered PHR is pendingfor transmission.
 19. The WTRU of claim 18, wherein the SCell isactivated on condition that the determined activation/deactivation statecommands an activation of the SCell.
 20. The WTRU of claim 18, whereinthe SCell is deactivated on condition that the determinedactivation/deactivation state commands a deactivation of the SCell. 21.The WTRU of claim 18, wherein the processor is further configured to: ona condition that the SCell is configured for reception of a physicaldownlink control channel, start a monitoring of the physical downlinkcontrol channel in response to activation of the SCell.
 22. The WTRU ofclaim 18, wherein the processor is further configured to: receive across-carrier scheduling configuration; and determine, from thecross-carrier scheduling configuration, a starting symbol of a physicaldownlink shared channel for the SCell.
 23. The WTRU of claim 18, whereinthe processor is further configured to: responsive to deactivation ofthe SCell, stop a monitoring of a physical downlink control channel forthe SCell; and stop receiving downlink assignments or uplink grantsassociated with the SCell.
 24. The WTRU of claim 18, wherein theprocessor is further configured to: receive a cross-carrier schedulingconfiguration; and determine, based on the cross-carrier schedulingconfiguration, a serving cell for receiving downlink allocations oruplink grants for the SCell.
 25. The WTRU of claim 18, wherein theprocessor is further configured to: responsive to deactivation of theSCell, stop a reporting of a channel quality indicator, a precodingmatrix index, or a rank indication for the SCell.
 26. The WTRU of claim18, wherein the processor is further configured to: responsive todeactivation of the SCell, release a sounding reference signal reportingconfiguration for the SCell.
 27. The WTRU of claim 18, wherein theprocessor is further configured to: release a configuration for theSCell responsive to an indication of a radio resource controllerconnection re-establishment.
 28. The WTRU of claim 18, wherein theactivation/deactivation MAC CE includes a bitmap, and wherein each bitin the bitmap corresponds to, and indicates the activation/deactivationstates of, one of the multiple SCells.
 29. The WTRU of claim 18, whereinthe SCell is initially configured in a deactivated state.
 30. The WTRUof claim 18, wherein the SCell is configured using an SCellconfiguration received via dedicated signaling, and wherein the SCellconfiguration comprises the identity of the SCell and a radio resourceconfiguration that identifies configuration parameters for downlink (DL)and uplink (UL) resources of the SCell.
 31. The WTRU of claim 18,wherein a deactivation timer is started or restarted responsive to theactivation/deactivation MAC CE signaling activation of the SCell. 32.The WTRU of claim 31, wherein the activation/deactivation MAC CE isreceived prior to expiry of the deactivation timer.
 33. The WTRU ofclaim 18, wherein the processor is further configured to transmit theMAC PDU at the next available transmission opportunity.
 34. The WTRU ofclaim 18, wherein the PHR MAC CE includes a valid PHR value for at leastthe SCell.